Local models of Gauge Mediated Supersymmetry Breaking in String Theory

小学下册英语第一单元测验试卷英语试题一、综合题(本题有50小题，每小题1分，共100分.每小题不选、错误，均不给分)1 What do we call a person who studies marine life?A. Marine BiologistB. OceanographerC. Aquatic ScientistD. All of the above2 What color is a school bus?A. BlueB. YellowC. GreenD. Red3 The discovery of ________ has fundamentally altered our understanding of physics.4 The _____ (小鸟) chirps happily in the morning.5 The country known for its historical architecture is ________ (希腊).6 The __________ (水果) is sweet and juicy.7 What color are ripe bananas?A. GreenB. RedC. Yellow答案:C8 A flashlight uses a _______ to produce light.9 My mom is a ______. She enjoys knitting.10 A catalyst lowers the ______ energy of a reaction.11 What is the most widely spoken language in the world?A. EnglishB. SpanishC. ChineseD. Hindi答案: C12 The capital of Marshall Islands is _______.13 The cookies are fresh and ___ (crispy/soft).14 A fern is a type of ______ (蕨类植物).15 A precipitate forms when two solutions _____ together.16 A ________ (土地) can be fertile or barren.17 A ____ has a spiny back and can curl into a ball for protection.18 I believe that learning from our mistakes helps us __________.19 I like to _______ (paint) with watercolors.20 We are going to ___ a trip. (take)21 What is the name of the famous ship that sank in 1912?A. BritannicB. TitanicC. LusitaniaD. Queen Mary22 小驴) brays loudly in the stable. The ___23 What do we call the largest land animal?A. RhinoB. ElephantC. GiraffeD. Hippo答案: B. Elephant24 The __________ is a famous beach destination.25 What do we call the sport played on ice with skates?A. SoccerB. BasketballC. Ice HockeyD. Football答案:C26 We have a ______ (有趣的) project in science class.27 The capital of Egypt is ________ (埃及的首都是________).28 A ______ (生态教育) can raise awareness about conservation.29 A ______ often hops around.30 What do we call the science of studying the stars and planets?A. BiologyB. ChemistryC. AstronomyD. Physics答案: C31 What is the shape of a soccer ball?A. SquareB. RectangleC. CircleD. Oval答案: C32 Which of these is a marine animal?A. EagleB. SharkC. LionD. Elephant33 The garden has many _____ (flowers/plants).34 My family goes _____ every winter. (skiing)35 I like to play with my ________ at home.36 The __________ (人类创新) leads to solutions.37 What do we call the study of ancient civilizations?A. AnthropologyB. ArchaeologyC. HistoryD. Sociology答案:B. Archaeology38 What do we call a person who studies the effects of space on human behavior?A. Space PsychologistB. SociologistC. AnthropologistD. Biologist答案: A39 The ______ is a layer of rock that lies directly beneath the Earth's surface.40 Which fruit is known for having seeds on the outside?A. StrawberryB. RaspberryC. BlackberryD. Blueberry答案：A41 The chameleon can blend into its _________. (环境)42 What is the name of the animal that hops and has a pouch?A. KangarooB. DogC. CatD. Lion答案: A43 The test is _____ (easy/hard).44 A _____ is a natural elevation of the Earth's surface.45 What do we wear on our feet?A. HatB. GlovesC. ShoesD. Scarf46 My brother plays the _____ guitar. (electric)47 _______ are important for the environment.48 What is the capital of Mexico?A. CancunB. GuadalajaraC. Mexico CityD. Monterrey答案: C49 What is the main ingredient in hummus?A. ChickpeasB. BeansC. LentilsD. Peas50 I planted some __________ (香草) in my kitchen garden.51 What do you call a collection of maps?A. AtlasB. BookC. EncyclopediaD. Dictionary答案:A52 What is the capital of Seychelles?A. VictoriaB. MahéC. PraslinD. La Digue答案:A53 I want to ___ a scientist. (become)54 What do we call the place where we learn?A. LibraryB. SchoolC. ParkD. Store答案:B55 What is the opposite of dark?A. LightB. BrightC. ClearD. All of the above答案:D56 The ________ (appliance) helps with chores.57 Gardening can help promote ______ (身心健康).58 The country that has a maple syrup tradition is ________ (加拿大).59 How do you spell "cat"?A. KatB. CatC. KattD. Catt答案:B60 The invention of the __________ changed communication forever. (电话)61 My grandpa loves to . (我爷爷喜欢。

19StandardMath ToolsDisplay up to four math function traces (F1-F4). The easy-to-use graphical interface simplifies setup of up to two operations on each function trace;and function traces can be chained together to perform math-on-math.absolute value integralaverage (summed)invert (negate)average (continuous)log (base e)custom (MATLAB) – limited points product (x)derivativeratio (/)deskew (resample)reciprocaldifference (–)rescale (with units)enhanced resolution (to 11 bits vertical)roof envelope (sinx)/x exp (base e)square exp (base 10)square root fft (power spectrum, magnitude, phase,sum (+)up to 50 kpts) trend (datalog) of 1000 events floorzoom (identity)histogram of 1000 eventsMeasure ToolsDisplay any 6 parameters together with statistics, including their average,high, low, and standard deviations. Histicons provide a fast, dynamic view of parameters and wave-shape characteristics.Pass/Fail TestingSimultaneously test multiple parameters against selectable parameter limits or pre-defined masks. Pass or fail conditions can initiate actions including document to local or networked files, e-mail the image of the failure, save waveforms, send a pulse out at the rear panel auxiliary BNC output, or (with the GPIB option) send a GPIB SRQ.Jitter and Timing Analysis Software Package (WRXi-JTA2)(Standard with MXi-A model oscilloscopes)•Jitter and timing parameters, with “Track”graphs of •Edge@lv parameter (counts edges)• Persistence histogram, persistence trace (mean, range, sigma)Software Options –Advanced Math and WaveShape AnalysisStatistics Package (WRXi-STAT)This package provides additional capability to statistically display measurement information and to analyze results:• Histograms expanded with 19 histogram parameters/up to 2 billion events.• Persistence Histogram• Persistence Trace (mean, range, sigma)Master Analysis Software Package (WRXi-XMAP)(Standard with MXi-A model oscilloscopes)This package provides maximum capability and flexibility, and includes all the functionality present in XMATH, XDEV, and JTA2.Advanced Math Software Package (WRXi-XMATH)(Standard with MXi-A model oscilloscopes)This package provides a comprehensive set of WaveShape Analysis tools providing insight into the wave shape of complex signals. Includes:•Parameter math – add, subtract, multiply, or divide two different parameters.Invert a parameter and rescale parameter values.•Histograms expanded with 19 histogram parameters/up to 2 billion events.•Trend (datalog) of up to 1 million events•Track graphs of any measurement parameter•FFT capability includes: power averaging, power density, real and imaginary components, frequency domain parameters, and FFT on up to 24 Mpts.•Narrow-band power measurements •Auto-correlation function •Sparse function• Cubic interpolation functionAdvanced Customization Software Package (WRXi-XDEV)(Standard with MXi-A model oscilloscopes)This package provides a set of tools to modify the scope and customize it to meet your unique needs. Additional capability provided by XDEV includes:•Creation of your own measurement parameter or math function, using third-party software packages, and display of the result in the scope. Supported third-party software packages include:– VBScript – MATLAB – Excel•CustomDSO – create your own user interface in a scope dialog box.• Addition of macro keys to run VBScript files •Support for plug-insValue Analysis Software Package (WRXi-XVAP)(Standard with MXi-A model oscilloscopes)Measurements:•Jitter and Timing parameters (period@level,width@level, edge@level,duty@level, time interval error@level, frequency@level, half period, setup, skew, Δ period@level, Δ width@level).Math:•Persistence histogram •Persistence trace (mean, sigma, range)•1 Mpts FFTs with power spectrum density, power averaging, real, imaginary, and real+imaginary settings)Statistical and Graphical Analysis•1 Mpts Trends and Histograms •19 histogram parameters •Track graphs of any measurement parameterIntermediate Math Software Package (WRXi-XWAV)Math:•1 Mpts FFTs with power spectrum density, power averaging, real, and imaginary componentsStatistical and Graphical Analysis •1 Mpts Trends and Histograms •19 histogram parameters•Track graphs of any measurement parameteramplitude area base cyclescustom (MATLAB,VBScript) –limited points delay Δdelay duration duty cyclefalltime (90–10%, 80–20%, @ level)firstfrequency lastlevel @ x maximum mean median minimumnumber of points +overshoot –overshoot peak-to-peak period phaserisetime (10–90%, 20–80%, @ level)rmsstd. deviation time @ level topΔ time @ levelΔ time @ level from triggerwidth (positive + negative)x@ max.x@ min.– Cycle-Cycle Jitter – N-Cycle– N-Cycle with start selection – Frequency– Period – Half Period – Width– Time Interval Error – Setup– Hold – Skew– Duty Cycle– Duty Cycle Error20WaveRunner WaveRunner WaveRunner WaveRunner WaveRunner 44Xi-A64Xi-A62Xi-A104Xi-A204Xi-AVertical System44MXi-A64MXi-A104MXi-A204MXi-ANominal Analog Bandwidth 400 MHz600 MHz600 MHz 1 GHz 2 GHz@ 50 Ω, 10 mV–1 V/divRise Time (Typical)875 ps500 ps500 ps300 ps180 psInput Channels44244Bandwidth Limiters20 MHz; 200 MHzInput Impedance 1 MΩ||16 pF or 50 Ω 1 MΩ||20 pF or 50 ΩInput Coupling50 Ω: DC, 1 MΩ: AC, DC, GNDMaximum Input Voltage50 Ω: 5 V rms, 1 MΩ: 400 V max.50 Ω: 5 V rms, 1 MΩ: 250 V max.(DC + Peak AC ≤ 5 kHz)(DC + Peak AC ≤ 10 kHz)Vertical Resolution8 bits; up to 11 with enhanced resolution (ERES)Sensitivity50 Ω: 2 mV/div–1 V/div fully variable; 1 MΩ: 2 mV–10 V/div fully variableDC Gain Accuracy±1.0% of full scale (typical); ±1.5% of full scale, ≥ 10 mV/div (warranted)Offset Range50 Ω: ±1 V @ 2–98 mV/div, ±10 V @ 100 mV/div–1 V/div; 50Ω:±400mV@2–4.95mV/div,±1V@5–99mv/div,1 M Ω: ±1 V @ 2–98 mV/div, ±10 V @ 100 mV/div–1 V/div,±10 V @ 100 mV–1 V/div±**********/div–10V/div 1 M Ω: ±400 mV @ 2–4.95 mV/div, ±1 V @5–99 mV/div, ±10 V @ 100 mV–1 V/div,±*********–10V/divInput Connector ProBus/BNCTimebase SystemTimebases Internal timebase common to all input channels; an external clock may be applied at the auxiliary inputTime/Division Range Real time: 200 ps/div–10 s/div, RIS mode: 200 ps/div to 10 ns/div, Roll mode: up to 1,000 s/divClock Accuracy≤ 5 ppm @ 25 °C (typical) (≤ 10 ppm @ 5–40 °C)Sample Rate and Delay Time Accuracy Equal to Clock AccuracyChannel to Channel Deskew Range±9 x time/div setting, 100 ms max., each channelExternal Sample Clock DC to 600 MHz; (DC to 1 GHz for 104Xi-A/104MXi-A and 204Xi-A/204MXi-A) 50 Ω, (limited BW in 1 MΩ),BNC input, limited to 2 Ch operation (1 Ch in 62Xi-A), (minimum rise time and amplitude requirements applyat low frequencies)Roll Mode User selectable at ≥ 500 ms/div and ≤100 kS/s44Xi-A64Xi-A62Xi-A104Xi-A204Xi-A Acquisition System44MXi-A64MXi-A104MXi-A204MXi-ASingle-Shot Sample Rate/Ch 5 GS/sInterleaved Sample Rate (2 Ch) 5 GS/s10 GS/s10 GS/s10 GS/s10 GS/sRandom Interleaved Sampling (RIS)200 GS/sRIS Mode User selectable from 200 ps/div to 10 ns/div User selectable from 100 ps/div to 10 ns/div Trigger Rate (Maximum) 1,250,000 waveforms/secondSequence Time Stamp Resolution 1 nsMinimum Time Between 800 nsSequential SegmentsAcquisition Memory Options Max. Acquisition Points (4 Ch/2 Ch, 2 Ch/1 Ch in 62Xi-A)Segments (Sequence Mode)Standard12.5M/25M10,00044Xi-A64Xi-A62Xi-A104Xi-A204Xi-A Acquisition Processing44MXi-A64MXi-A104MXi-A204MXi-ATime Resolution (min, Single-shot)200 ps (5 GS/s)100 ps (10 GS/s)100 ps (10 GS/s)100 ps (10 GS/s)100 ps (10 GS/s) Averaging Summed and continuous averaging to 1 million sweepsERES From 8.5 to 11 bits vertical resolutionEnvelope (Extrema)Envelope, floor, or roof for up to 1 million sweepsInterpolation Linear or (Sinx)/xTrigger SystemTrigger Modes Normal, Auto, Single, StopSources Any input channel, External, Ext/10, or Line; slope and level unique to each source, except LineTrigger Coupling DC, AC (typically 7.5 Hz), HF Reject, LF RejectPre-trigger Delay 0–100% of memory size (adjustable in 1% increments, or 100 ns)Post-trigger Delay Up to 10,000 divisions in real time mode, limited at slower time/div settings in roll modeHold-off 1 ns to 20 s or 1 to 1,000,000,000 events21WaveRunner WaveRunner WaveRunner WaveRunner WaveRunner 44Xi-A 64Xi-A 62Xi-A104Xi-A 204Xi-A Trigger System (cont’d)44MXi-A64MXi-A104MXi-A204MXi-AInternal Trigger Level Range ±4.1 div from center (typical)Trigger and Interpolator Jitter≤ 3 ps rms (typical)Trigger Sensitivity with Edge Trigger 2 div @ < 400 MHz 2 div @ < 600 MHz 2 div @ < 600 MHz 2 div @ < 1 GHz 2 div @ < 2 GHz (Ch 1–4 + external, DC, AC, and 1 div @ < 200 MHz 1 div @ < 200 MHz 1 div @ < 200 MHz 1 div @ < 200 MHz 1 div @ < 200 MHz LFrej coupling)Max. Trigger Frequency with400 MHz 600 MHz 600 MHz 1 GHz2 GHzSMART Trigger™ (Ch 1–4 + external)@ ≥ 10 mV@ ≥ 10 mV@ ≥ 10 mV@ ≥ 10 mV@ ≥ 10 mVExternal Trigger RangeEXT/10 ±4 V; EXT ±400 mVBasic TriggersEdgeTriggers when signal meets slope (positive, negative, either, or Window) and level conditionTV-Composite VideoT riggers NTSC or PAL with selectable line and field; HDTV (720p, 1080i, 1080p) with selectable frame rate (50 or 60 Hz)and Line; or CUSTOM with selectable Fields (1–8), Lines (up to 2000), Frame Rates (25, 30, 50, or 60 Hz), Interlacing (1:1, 2:1, 4:1, 8:1), or Synch Pulse Slope (Positive or Negative)SMART TriggersState or Edge Qualified Triggers on any input source only if a defined state or edge occurred on another input source.Delay between sources is selectable by time or eventsQualified First In Sequence acquisition mode, triggers repeatedly on event B only if a defined pattern, state, or edge (event A) is satisfied in the first segment of the acquisition. Delay between sources is selectable by time or events Dropout Triggers if signal drops out for longer than selected time between 1 ns and 20 s.PatternLogic combination (AND, NAND, OR, NOR) of 5 inputs (4 channels and external trigger input – 2 Ch+EXT on WaveRunner 62Xi-A). Each source can be high, low, or don’t care. The High and Low level can be selected independently. Triggers at start or end of the patternSMART Triggers with Exclusion TechnologyGlitch and Pulse Width Triggers on positive or negative glitches with widths selectable from 500 ps to 20 s or on intermittent faults (subject to bandwidth limit of oscilloscope)Signal or Pattern IntervalTriggers on intervals selectable between 1 ns and 20 sTimeout (State/Edge Qualified)Triggers on any source if a given state (or transition edge) has occurred on another source.Delay between sources is 1 ns to 20 s, or 1 to 99,999,999 eventsRuntTrigger on positive or negative runts defined by two voltage limits and two time limits. Select between 1 ns and 20 sSlew RateTrigger on edge rates. Select limits for dV, dt, and slope. Select edge limits between 1 ns and 20 s Exclusion TriggeringTrigger on intermittent faults by specifying the normal width or periodLeCroy WaveStream Fast Viewing ModeIntensity256 Intensity Levels, 1–100% adjustable via front panel control Number of Channels up to 4 simultaneouslyMax Sampling Rate5 GS/s (10 GS/s for WR 62Xi-A, 64Xi-A/64MXi-A,104Xi-A/104MXi-A, 204Xi-A/204MXi-A in interleaved mode)Waveforms/second (continuous)Up to 20,000 waveforms/secondOperationFront panel toggle between normal real-time mode and LeCroy WaveStream Fast Viewing modeAutomatic SetupAuto SetupAutomatically sets timebase, trigger, and sensitivity to display a wide range of repetitive signalsVertical Find ScaleAutomatically sets the vertical sensitivity and offset for the selected channels to display a waveform with maximum dynamic range44Xi-A 64Xi-A 62Xi-A104Xi-A 204Xi-A Probes44MXi-A 64MXi-A104MXi-A 204MXi-AProbesOne Passive probe per channel; Optional passive and active probes available Probe System; ProBus Automatically detects and supports a variety of compatible probes Scale FactorsAutomatically or manually selected, depending on probe usedColor Waveform DisplayTypeColor 10.4" flat-panel TFT-LCD with high resolution touch screenResolutionSVGA; 800 x 600 pixels; maximum external monitor output resolution of 2048 x 1536 pixelsNumber of Traces Display a maximum of 8 traces. Simultaneously display channel, zoom, memory, and math traces Grid StylesAuto, Single, Dual, Quad, Octal, XY , Single + XY , Dual + XY Waveform StylesSample dots joined or dots only in real-time mode22Zoom Expansion TracesDisplay up to 4 Zoom/Math traces with 16 bits/data pointInternal Waveform MemoryM1, M2, M3, M4 Internal Waveform Memory (store full-length waveform with 16 bits/data point) or store to any number of files limited only by data storage mediaSetup StorageFront Panel and Instrument StatusStore to the internal hard drive, over the network, or to a USB-connected peripheral deviceInterfaceRemote ControlVia Windows Automation, or via LeCroy Remote Command Set Network Communication Standard VXI-11 or VICP , LXI Class C Compliant GPIB Port (Accessory)Supports IEEE – 488.2Ethernet Port 10/100/1000Base-T Ethernet interface (RJ-45 connector)USB Ports5 USB 2.0 ports (one on front of instrument) supports Windows-compatible devices External Monitor Port Standard 15-pin D-Type SVGA-compatible DB-15; connect a second monitor to use extended desktop display mode with XGA resolution Serial PortDB-9 RS-232 port (not for remote oscilloscope control)44Xi-A 64Xi-A 62Xi-A104Xi-A 204Xi-A Auxiliary Input44MXi-A 64MXi-A104MXi-A 204MXi-ASignal Types Selected from External Trigger or External Clock input on front panel Coupling50 Ω: DC, 1 M Ω: AC, DC, GND Maximum Input Voltage50 Ω: 5 V rms , 1 M Ω: 400 V max.50 Ω: 5 V rms , 1 M Ω: 250 V max. (DC + Peak AC ≤ 5 kHz)(DC + Peak AC ≤ 10 kHz)Auxiliary OutputSignal TypeTrigger Enabled, Trigger Output. Pass/Fail, or Off Output Level TTL, ≈3.3 VConnector TypeBNC, located on rear panelGeneralAuto Calibration Ensures specified DC and timing accuracy is maintained for 1 year minimumCalibratorOutput available on front panel connector provides a variety of signals for probe calibration and compensationPower Requirements90–264 V rms at 50/60 Hz; 115 V rms (±10%) at 400 Hz, Automatic AC Voltage SelectionInstallation Category: 300 V CAT II; Max. Power Consumption: 340 VA/340 W; 290 VA/290 W for WaveRunner 62Xi-AEnvironmentalTemperature: Operating+5 °C to +40 °C Temperature: Non-Operating -20 °C to +60 °CHumidity: Operating Maximum relative humidity 80% for temperatures up to 31 °C decreasing linearly to 50% relative humidity at 40 °CHumidity: Non-Operating 5% to 95% RH (non-condensing) as tested per MIL-PRF-28800F Altitude: OperatingUp to 3,048 m (10,000 ft.) @ ≤ 25 °C Altitude: Non-OperatingUp to 12,190 m (40,000 ft.)PhysicalDimensions (HWD)260 mm x 340 mm x 152 mm Excluding accessories and projections (10.25" x 13.4" x 6")Net Weight7.26kg. (16.0lbs.)CertificationsCE Compliant, UL and cUL listed; Conforms to EN 61326, EN 61010-1, UL 61010-1 2nd Edition, and CSA C22.2 No. 61010-1-04Warranty and Service3-year warranty; calibration recommended annually. Optional service programs include extended warranty, upgrades, calibration, and customization services23Product DescriptionProduct CodeWaveRunner Xi-A Series Oscilloscopes2 GHz, 4 Ch, 5 GS/s, 12.5 Mpts/ChWaveRunner 204Xi-A(10 GS/s, 25 Mpts/Ch in interleaved mode)with 10.4" Color Touch Screen Display 1 GHz, 4 Ch, 5 GS/s, 12.5 Mpts/ChWaveRunner 104Xi-A(10 GS/s, 25 Mpts/Ch in interleaved mode)with 10.4" Color Touch Screen Display 600 MHz, 4 Ch, 5 GS/s, 12.5 Mpts/Ch WaveRunner 64Xi-A(10 GS/s, 25 Mpts/Ch in interleaved mode)with 10.4" Color Touch Screen Display 600 MHz, 2 Ch, 5 GS/s, 12.5 Mpts/Ch WaveRunner 62Xi-A(10 GS/s, 25 Mpts/Ch in interleaved mode)with 10.4" Color Touch Screen Display 400 MHz, 4 Ch, 5 GS/s, 12.5 Mpts/Ch WaveRunner 44Xi-A(25 Mpts/Ch in interleaved mode)with 10.4" Color Touch Screen DisplayWaveRunner MXi-A Series Oscilloscopes2 GHz, 4 Ch, 5 GS/s, 12.5 Mpts/ChWaveRunner 204MXi-A(10 GS/s, 25 Mpts/Ch in Interleaved Mode)with 10.4" Color Touch Screen Display 1 GHz, 4 Ch, 5 GS/s, 12.5 Mpts/ChWaveRunner 104MXi-A(10 GS/s, 25 Mpts/Ch in Interleaved Mode)with 10.4" Color Touch Screen Display 600 MHz, 4 Ch, 5 GS/s, 12.5 Mpts/Ch WaveRunner 64MXi-A(10 GS/s, 25 Mpts/Ch in Interleaved Mode)with 10.4" Color Touch Screen Display 400 MHz, 4 Ch, 5 GS/s, 12.5 Mpts/Ch WaveRunner 44MXi-A(25 Mpts/Ch in Interleaved Mode)with 10.4" Color Touch Screen DisplayIncluded with Standard Configuration÷10, 500 MHz, 10 M Ω Passive Probe (Total of 1 Per Channel)Standard Ports; 10/100/1000Base-T Ethernet, USB 2.0 (5), SVGA Video out, Audio in/out, RS-232Optical 3-button Wheel Mouse – USB 2.0Protective Front Cover Accessory PouchGetting Started Manual Quick Reference GuideAnti-virus Software (Trial Version)Commercial NIST Traceable Calibration with Certificate 3-year WarrantyGeneral Purpose Software OptionsStatistics Software Package WRXi-STAT Master Analysis Software Package WRXi-XMAP (Standard with MXi-A model oscilloscopes)Advanced Math Software Package WRXi-XMATH (Standard with MXi-A model oscilloscopes)Intermediate Math Software Package WRXi-XWAV (Standard with MXi-A model oscilloscopes)Value Analysis Software Package (Includes XWAV and JTA2) WRXi-XVAP (Standard with MXi-A model oscilloscopes)Advanced Customization Software Package WRXi-XDEV (Standard with MXi-A model oscilloscopes)Spectrum Analyzer and Advanced FFT Option WRXi-SPECTRUM Processing Web Editor Software Package WRXi-XWEBProduct Description Product CodeApplication Specific Software OptionsJitter and Timing Analysis Software Package WRXi-JTA2(Standard with MXi-A model oscilloscopes)Digital Filter Software PackageWRXi-DFP2Disk Drive Measurement Software Package WRXi-DDM2PowerMeasure Analysis Software Package WRXi-PMA2Serial Data Mask Software PackageWRXi-SDM QualiPHY Enabled Ethernet Software Option QPHY-ENET*QualiPHY Enabled USB 2.0 Software Option QPHY-USB †EMC Pulse Parameter Software Package WRXi-EMC Electrical Telecom Mask Test PackageET-PMT* TF-ENET-B required. †TF-USB-B required.Serial Data OptionsI 2C Trigger and Decode Option WRXi-I2Cbus TD SPI Trigger and Decode Option WRXi-SPIbus TD UART and RS-232 Trigger and Decode Option WRXi-UART-RS232bus TD LIN Trigger and Decode Option WRXi-LINbus TD CANbus TD Trigger and Decode Option CANbus TD CANbus TDM Trigger, Decode, and Measure/Graph Option CANbus TDM FlexRay Trigger and Decode Option WRXi-FlexRaybus TD FlexRay Trigger and Decode Physical Layer WRXi-FlexRaybus TDP Test OptionAudiobus Trigger and Decode Option WRXi-Audiobus TDfor I 2S , LJ, RJ, and TDMAudiobus Trigger, Decode, and Graph Option WRXi-Audiobus TDGfor I 2S LJ, RJ, and TDMMIL-STD-1553 Trigger and Decode Option WRXi-1553 TDA variety of Vehicle Bus Analyzers based on the WaveRunner Xi-A platform are available.These units are equipped with a Symbolic CAN trigger and decode.Mixed Signal Oscilloscope Options500 MHz, 18 Ch, 2 GS/s, 50 Mpts/Ch MS-500Mixed Signal Oscilloscope Option 250 MHz, 36 Ch, 1 GS/s, 25 Mpts/ChMS-500-36(500 MHz, 18 Ch, 2 GS/s, 50 Mpts/Ch Interleaved) Mixed Signal Oscilloscope Option 250 MHz, 18 Ch, 1 GS/s, 10 Mpts/Ch MS-250Mixed Signal Oscilloscope OptionProbes and Amplifiers*Set of 4 ZS1500, 1.5 GHz, 0.9 pF , 1 M ΩZS1500-QUADPAK High Impedance Active ProbeSet of 4 ZS1000, 1 GHz, 0.9 pF , 1 M ΩZS1000-QUADPAK High Impedance Active Probe 2.5 GHz, 0.7 pF Active Probe HFP25001 GHz Active Differential Probe (÷1, ÷10, ÷20)AP034500 MHz Active Differential Probe (x10, ÷1, ÷10, ÷100)AP03330 A; 100 MHz Current Probe – AC/DC; 30 A rms ; 50 A rms Pulse CP03130 A; 50 MHz Current Probe – AC/DC; 30 A rms ; 50 A rms Pulse CP03030 A; 50 MHz Current Probe – AC/DC; 30 A rms ; 50 A peak Pulse AP015150 A; 10 MHz Current Probe – AC/DC; 150 A rms ; 500 A peak Pulse CP150500 A; 2 MHz Current Probe – AC/DC; 500 A rms ; 700 A peak Pulse CP5001,400 V, 100 MHz High-Voltage Differential Probe ADP3051,400 V, 20 MHz High-Voltage Differential Probe ADP3001 Ch, 100 MHz Differential Amplifier DA1855A*A wide variety of other passive, active, and differential probes are also available.Consult LeCroy for more information.Product Description Product CodeHardware Accessories*10/100/1000Base-T Compliance Test Fixture TF-ENET-B †USB 2.0 Compliance Test Fixture TF-USB-B External GPIB Interface WS-GPIBSoft Carrying Case WRXi-SOFTCASE Hard Transit CaseWRXi-HARDCASE Mounting Stand – Desktop Clamp Style WRXi-MS-CLAMPRackmount Kit WRXi-RACK Mini KeyboardWRXi-KYBD Removable Hard Drive Package (Includes removeable WRXi-A-RHD hard drive kit and two hard drives)Additional Removable Hard DriveWRXi-A-RHD-02* A variety of local language front panel overlays are also available .† Includes ENET-2CAB-SMA018 and ENET-2ADA-BNCSMA.Customer ServiceLeCroy oscilloscopes and probes are designed, built, and tested to ensure high reliability. In the unlikely event you experience difficulties, our digital oscilloscopes are fully warranted for three years, and our probes are warranted for one year.This warranty includes:• No charge for return shipping • Long-term 7-year support• Upgrade to latest software at no chargeLocal sales offices are located throughout the world. Visit our website to find the most convenient location.© 2010 by LeCroy Corporation. All rights reserved. Specifications, prices, availability, and delivery subject to change without notice. Product or brand names are trademarks or requested trademarks of their respective holders.1-800-5-LeCroy WRXi-ADS-14Apr10PDF。

《11规则》题库第二章航海仪器测试题基本信息：[矩阵文本题] *1. ______ is not required by bridge-to-bridge communications. [单选题] *VHFSARTNAVTEXLES(正确答案)2. As for Racon, which one is incorrect in the following? [单选题] *Racon is a radar transponderRacon is often installed on major waypointsWhen activated by a radar signal, the Racon sends it back with an identifier Racon can be used to take place of radar(正确答案)3. PAN-PAN repeated three times over the radiotelephone indicates which type of message will follow? [单选题] *DistressSafetyAll clearUrgency(正确答案)4. Automatic identification systems (AIS) are expected to broadcast all of the following information except ______. [单选题] *port of origin(正确答案)name of vesselcourse and speed over grounddraft of vessel5. What does a navigator who uses an ECDIS require? [单选题] *Good navigational knowledge and a professional job attitude(正确答案)Good computer knowledgeGood system knowledgeNothing special6. The terrestrial system of GMDSS consists of ____________. [单选题] *radio-telephony, DSC, Direct Printing Telegraphy, Navtex and SART(正确答案) INMARSAT, DSC, Direct Printing Telegraphy, Navtex and SARTradio-telephony, DSC, EPIRB, Navtex and SARTStatus Recording system, DSC, Direct Printing Telegraphy, Navtex and SART7. The ______ provides the link between the Space Segment and the land-based National/International fixed communications networks. [单选题] *VHFSARTNAVTEXLES(正确答案)8. If the electronic chart is part of an ECDIS, it must display the minimum data required by IMO/IHO, to include all the following EXCEPT ______. [单选题] *hydrographyaids to navigationtidal current(正确答案)regulatory boundaries9. When a call is complete，and subsequently during an exchange of messages，a station invites a reply by saying ___. [单选题] *“Over”(正确答案)“Out”“OK”“Roger”10. What is the correct speed input to an ARPA used for traffic surveillance? [单选题] *Ground speedSpeed through water(正确答案)Speed from GPSSpeed from Doppler11. All echo-sounders can measure the ______. [单选题] *actual depth of wateractual depth of water below keel(正确答案)average depth from waterline to hard bottomaverage depth of water to soft bottom12. A satellite navigation system with global coverage may be termed as global navigation satellite system or _____. [单选题] *GNSS(正确答案)EPIRBSSASECDIS13. The VDR system is designed to operate_____ once it is set up correctly. There is no user interaction . [单选题] *automatically(正确答案)accuratelypromptlyConspicuously14. What is the MOST important thing you should do before transmitting on a marine radio? [单选题] *Ask for permissionRecord the time in your radio logPress the push to talk button three timeMonitor the channel to ensure that it is clear(正确答案)15. While underway, a vessel over 100,000 gross tons with an automatic identification system (AIS) is expected to broadcast all of the following information every 1 to 10 seconds EXCEPT ______. [单选题] *rate of turnname of the vessel(正确答案)navigational statusship’s heading16. The GPS system was designed for ______ satellites. [单选题] *3121824(正确答案)17. What is important to check when transferring a position from GPS to a chart? [单选题] *Reading the position correctlyPlotting the position correctlyMake sure that the chart and the GPS use same datum(正确答案)Make sure the map is updated18. You are using a radar in which your own ship is shown at the center, and the heading flash always points to 0 degree, If bearings are measured in relation to the flash, what type of bearings are produced? ______. [单选题] *Relative(正确答案)TrueCompassMagnetic19. The compass error of a magnetic compass that has no deviation is ______. [单选题] *zeroequal to variation(正确答案)eliminated by adjusting the compassconstant at any geographical location20. A radar range to a small，charted object such as a light will provide a line of position in the form of ______. [单选题] *straight linearc(正确答案)parabolahyperbola21. You have another ship overtaking you close aboard to starboard. You have 3 radar targets bearing 090，0.5 mile, 1 mile，and 1.5 miles. In this case，the unwanted echoes are called ______. [单选题] *Multiple echoes(正确答案)SpokingIndirect echoesSide-lobe echoes22. What is the main purpose of DGPS? [单选题] *Improve positioning accuracy(正确答案)Decrease positioning accuracyReduce operational costI don't know23. When it is accepted to remain on the frequency indicated，you should say ______. [单选题] *standing by on VHF frequency(正确答案)coming to VHF frequencyVHF frequency is the best place for you to stay byremaining in frequency and do not change24. The satellite systems of GMDSS comprise ______. [单选题] *NAVTEX, COSPAS/SARSAT, EPIRBs and Status Recording-systemInmarsat, COSPAS/SARSAT, EPIRBs and Status Recording-system(正确答案) NAVTEX, Inmarsat, EPIRBs and SARTInmarsat, Direct Printing Telegraphy, and DSC25. When another calling channel/frequency is available，do not use ______ or other safety frequencies to make a transmission. [单选题] *2182 kHz or VHF Channel 16(正确答案)VHF Channel 76FAXCABLES26. How to reduce beam width distortion? [单选题] *Adjust centre positionAdjust brillianceAdjust heading markerReduce gain(正确答案)27. ______ is on the panel of DF. [单选题] *ZERO CLEARING(正确答案)ANTI-CLUTTER-RAINDIMMERCURSOR28. In radiotelephony，the spoken word for distress is ______. [单选题] *SecuriteSafetyEmergencyMAYDAY(正确答案)29. Which one of the followings is incorrect about magnetic compass? [单选题] *The magnetic compass is compulsory on my vesselThe magnetic compass is prone to errorThe magnetic compass is always placed inside steel constructions(正确答案)The magnetic compass needs to be calibrated to compensate for local magnetic distortion 30. Radar reflectors are required for ______. [单选题] *all fishing vessels over 39 feet in lengthsail-propelled fishing vesselsall fishing vessels of less than 200 GTwooden hull fishing vessels with a poor radar echo(正确答案)31. If there were suddenly an immediate danger for both the vessel and its crew, would you send a MAYDAY on__ [单选题] *Ch06 with dual watchCh06 with 25 watts outputCh16 with 1 watt outputCh16 with 25 watts output(正确答案)32. The line connecting the Loran-C master station with a secondary station is called the ______. [单选题] *focus linebase line(正确答案)side linecenter line33. If a GMDSS radio operator initiates a DSC distress transmission but does not insert a message，what happens? [单选题] *The transmission is aborted and an alarm sounds to indicate this data must be provided by the operatorThe transmission is not initiated and “ERROR” is indicated on the display readoutThe transmission will be made with “default” information provided automatically(正确答案)The receiving station will poll the DSC unit of the vessel in distress to download the necessary information34. Ship to ship communications during SAR should be executed by _____. [单选题] * VHFMFSatelliteVHF and MF(正确答案)35. The indicated heading should not be relied on ________. [单选题] *until the gyrocompass has settled(正确答案)until the “Ready” lamp will be litwhen the alarm is generatedwhen the red “Power” lamp RCU illuminates36. When your vessel is proceeding to the area of traffic density，______ is used to determine the exact ranges of other ships or objects in the vicinity. [单选题] * Radar(正确答案)GPSDFSatellite Navigator37. Magnetic heading differs from compass heading by _______. [单选题] * compass errortrue headingvariationdeviation(正确答案)38. What is the primary equipment for receiving MSI ________. [单选题] *SARTEPIRBNAVTEX(正确答案)INMARSAT-B39. If the gyrocompass error is east，what describes the error and the correction to be made to gyrocompass headings to obtain true headings ________. [单选题] *The readings are too low（small numerically）and the amount of the error must be added to the compass to obtain true(正确答案)The readings are too low and the amount of the error must be subtracted from the compass to obtain trueThe readings are too high（large numerically）and the amount of the error must be added to the compass to obtain trueThe readings are too high and the amount of the error must be subtracted from the compass to obtain true40. If the magnetic heading is greater than the compass heading，the deviation is ______. [单选题] *east(正确答案)westnorthsouth41. Deviation which is maximum on intercardinal compass headings may be removed by the ______. [单选题] *Flinders barTransverse magnetsFore-and-aft magnetsSoft iron spheres on the sides of the compass(正确答案)42. The accuracy of the DGPS mainly depends on_______. [单选题] *the price of the equipmentthe relative angle between the satellitethe position of the observerthe age of the calculated correction(正确答案)43. Which statement concerning locating signals in the GMDSS is FALSE? [单选题] *Locating signals are transmitted by survival craft VHF transceivers.(正确答案) Locating signals are transmitted by SARTS.Locating signals are intended to facilitate the finding of a distressed vessel or its survivorsLocating signals are not transmitted by auto alarm generators.44. Coral atolls, or a chain of islands at right angles to the radar beam, may show as a long line rather as an individual targets due to ______. [单选题] *the effects of beam width(正确答案)limitations on range resolutionthe pulse length of the radarthe multiple-target resolution factor45. Quadrantal error in a gyrocompass has its greatest effect ______. [单选题] *in high latitudesnear the equatoron north or south headingson intercardinal headings(正确答案)46. What is important to remember when using AIS for collision avoidance? [单选题] *AIS may not give a complete picture of the traffic situation(正确答案)AIS is more accurate than ARPAAIS is not as accurate as ARPAAIS is not allowed to be used for collision avoidance47. Integrated Bridge and Navigation Systems (IBS/INS) provide excellent performance and reliable navigation under all conditions by _____. [单选题] *integrating well-proven, harmonizing equipment(正确答案)integrating all equipment in the bridgean intelligent platform with ECDIS and Radarthe control center based on ECDIS48. Which statement concerning GPS is TRUE ________. [单选题] *It cannot be used in all parts of the worldThere are 12 functioning GPS satellites at presentIt may be suspended without warning(正确答案)Two position lines are used to give a 2D fix49. When hitting a solid object such as a ship or an airplane, the radar waves are reflected back ______ they came. [单选题] *in the waythe wayby the waythrough the path(正确答案)50. A Doppler log in the volume reverberation mode indicates ______. [单选题] *speed being made goodspeed through the water(正确答案)the set of the currentthe depth of the water51. ECDIS must be able to perform all of the following EXCEPT ______. [单选题] *determine true bearing and distance between two geographical pointsdetermine magnetic compass deviation(正确答案)transform a local datum to the WGS-84 datumconvert “graphical coordinates” to “display coordinates”52. According to SOLAS the breathing air apparatus that must be onboard shall have sufficient capacity for how many minutes of operation? [单选题] *2030(正确答案)456053. Which factor has the greatest effect on the amount of gain required to obtain a fathometer reading? [单选题] *Salinity of waterTemperature of water(正确答案)Atmosphere pressureType of bottom54. Your ARPA has two guard zones. What is the purpose of the inner guard zone? [单选题] *Alert the watch officer that a vessel is approaching the preset CPA limitWarn of small targets that are initially detected closer than the outer guard zone(正确答案)Guard against target loss during critical maneuvering situationsSound an alarm for targets first detected within the zone55. ETA／PILOT REVERTING means [单选题] *ETA pilot station has been givenETA pilot station will be given afterwards(正确答案)ETA pilot station was not givenETA pilot station is given56. ________is used for providing homing signals from survival craft for detection by 9 GHz radar. [单选题] *NAVETEX receiverSearch and Rescue Transponder(正确答案)Emergency Position Indicating Radio BeaconDigital selective calling57. ______ is used for safety of navigation ship-to-ship. [单选题] *Channel 6Channel 13(正确答案)Channel 16Channel 7058. Which action should you take after sending a false distress alert on VHF? [单选题] *Send a DSC cancellation message on Ch-70.Make a voice announcement to cancel the alert on Ch-16.(正确答案)Make a voice announcement to cancel the alert on Ch-13.Make a voice announcement to cancel the alert on Ch-22A.59. ______ typically extends from close as 0.1 nautical miles out to 32 NM. [单选题] *EBLVRMCRTtarget tracking range(正确答案)60. When own ship’s position input to ECDIS is wrong, what is the result? [单选题] *NothingECDIS will give warningECDIS will automatically be switched offPosition, range and bearing taken on the ECDIS will be wrong(正确答案)61. The radar control used to reduce sea return at close ranges is the ______. [单选题] *Gain controlSensitivity time control(正确答案)Fast time constantPulse length control62. The common way to obtain your ship’s position is ______. [单选题] *keeping a close watch and lookouttaking a radar range and bearing(正确答案)observing a radar target and listening to signalskeeping a well clear caution63. A radar display in which North is always at the top of the screen is a（n）______. [单选题] *Unstabilized displayStabilized display(正确答案)Composition displayRelative display64. ______ is a radio receiver with ability to sense direction of the incoming radio waves. [单选题] *The echo sounderThe radarThe course recorderThe direction finder(正确答案)65. The abbreviation RYC in a marine cable generally stands for ______. [单选题] *referring to your crewreference for your captainreturn to your cabinreceived your cable(正确答案)66. How long must the GMDSS radio log be retained on board ________. [单选题] *At least two years after the last entry(正确答案)At least one year after the last entryAt least 90 days after the last entryAt least 30 days after the last entry67. The angular difference between the true meridian（great circle connecting the geographic poles）and the magnetic meridian（direction of the lines of magnetic flux）is called ______. [单选题] *deviationvariation(正确答案)errordifference68. If you receive the signal over radiotelephone of Romeo Papa Tango while using the International Code of Signals, you should ______. [单选题] *report to the callerrepeat your last transmission(正确答案)continue since he received your last transmissionend the transmission69. Deviation changes with a change in ______. [单选题] *latitudeheading(正确答案)longitudesea conditions70. How does current and drift effect the relative motion, relative vector presentation? [单选题] *No effect(正确答案)Producing small errors in calculated aspectProducing large errors in calculated aspectProduce errors in calculated CAP/TCPA71. A single vertical magnet placed underneath the compass in the binnacle is used to compensate for ______. [单选题] *the horizontal component of the permanent magnetismdeviation caused by the vessel's inclination from the vertical(正确答案)induced magnetism in the horizontal soft ironinduced magnetism in the vertical soft iron72. The receiver uses ______ satellites to compute latitude，longitude，altitude，and velocity. [单选题] *onetwothreefour(正确答案)73. ______ is used for calling and replying, and for transmitting acknowledging and relaying distress alerts. [单选题] *NAVTEX receiverSearch and Rescue TransponderEmergency Position Indicating Radio BeaconDigital selective calling(正确答案)74. How is an uncoded racon displayed on the PPI? [单选题] *As a line(正确答案)As a dotAs a small circleAs a large circle75. Variation is a compass error that you ______. [单选题] *can correct by adjusting the compass cardcan correct by adjusting the compensation magnetscan correct by changing the vessel’s headingcannot correct(正确答案)76. Before sailing, mariners on duty shall check the headings of magnetic compass by comparison with _____. [单选题] *ship’s clockengine movement recorderrepeaters(正确答案)navigation lights77. ____ is the navigational timekeeper of the vessel. [单选题] *The marine sextantThe chronometer(正确答案)The magnetic compassThe gyrocompass78. A(n) ______ indicates that there is serious and immediate danger for vessel, crew and passengers. [单选题] *distress alert(正确答案)urgency messagesafety messageroutine message79. Which one of the followings is a standard phrase? [单选题] *WARNING. You are running into danger.(正确答案)You are possibly running into danger.You could be in the case of running into danger.You could , I think , be running into danger.80. What is the right way to use VHF CH16 and working channel? [单选题] *Ships can call other ships on Ch16 but should move to a working channel as soon as possible.(正确答案)Ship should use working channel to call other ships at any time.Ch16 is only used as the international distress and calling frequency.Ship can use Ch16 or working channel as they like81. The ship LRIT system shall transmit the ship’s LRIT information at ______ to an LRIT DATA center ? [单选题] *1-hour interval2-hour interval3-hour interval6-hour intervals(正确答案)82. In ________ within coverage of an Inmarsat geostationary satellite, continuous alerting is available. [单选题] *Sea Area A1Sea Area A2Sea Area A3(正确答案)Sea Area A483. How to report your ship call sign to a shore station? [单选题] *Use capital lettersUse phonetic alphabet(正确答案)Use letters and numbersUse flag signals84. Any piece of metal on becoming magnetized will develop regions of concentrated magnetism called ______. [单选题] *fluxpoles(正确答案)magnetsazimuth85. ____ is used for measuring horizontal and vertical angles. [单选题] *The marine sextant(正确答案)The chronometerThe magnetic compassThe gyrocompass86. Which of the following is defined as static information? [单选题] *Navigational statusSafety related messageMMSI(正确答案)Route plan87. The ______ transmits own ship data cyclically via two defined VHF channels and receives the same data of the other ships and objects that are equipped with AIS systems. [单选题] *AIS(正确答案)ECDISGPSVDR88. What are the only magnetic compass correctors that correct for both permanent and induced effects of magnetism？ [单选题] *Quadrantal spheresHeeling magnets(正确答案)Athwartships magnetsFore-and-aft magnets89. All VHF marine band radios operate in the simplex mode, which means that ______. [单选题] *only one person may talk at a time(正确答案)only two persons may talk at the same timethe radio only transmitsthe radio only receives90. What type of radar can activate a racon? [单选题] *X-band radar(正确答案)S-band radarC-band radarNo radar can91. Your radar is set on a true motion display. Which of the following will NOT appear to move across the PPI scope? [单选题] *Echoes from a buoy(正确答案)Own ship's markerEcho from a ship on the same course at the same speedEcho from a ship on a reciprocal course at the same speed92. What is the spoken emergency signal for a “man overboard” on the VHF radio? [单选题] *Man OverboardSecurityMaydayPan-Pan(正确答案)93. When the transmissions of a radio station have broken down, switched off or suspended, it is _______. [单选题] *unfunctionalbreak downoff poweroff air(正确答案)94. The maritime radio system consisting of a series of coast stations transmitting coastal warning is called______. [单选题] *NAVTEX(正确答案)HYDROLANT/HYDROPACNAVAREASAFESEA95. If a magnetic compass is not affected by any magnetic field other than the Earth's，which statement is TRUE? [单选题] *Compass error and variation are equal(正确答案)Compass north will be true northVariation will equal deviationThere will be no compass error96. Which device provides the main means in the GMDSS for locating ships in distress or their survival craft? [单选题] *Radio direction finderSatellite EPIRBs(正确答案)MF/HF DSCVHF homing device97. The description of RACON beside an illustration on a chart would near a ______. [单选题] *radar conspicuous beaconcircular radiobeaconradar transponder beacon(正确答案)radar calibration beacon98. A navigator fixing a vessel’s position by radar______. [单选题] *should never use radar bearingsshould only use radar bearings when the range exceeds the distance to the horizoncan use radar information from one object to fix the position(正确答案)must use information from targets forward of the beam99. Lines on a chart which connect points of equal magnetic variation are called ______. [单选题] *Magnetic latitudesMagnetic declinationsDipIsogonic lines(正确答案)100. AMVER is a system which provides ______. [单选题] *satellite communicationsnavigational informationweather informationposition reporting service(正确答案)。

《2024年高考英语新课标卷真题深度解析与考后提升》专题05阅读理解D篇（新课标I卷）原卷版(专家评价+全文翻译+三年真题+词汇变式+满分策略+话题变式)目录一、原题呈现P2二、答案解析P3三、专家评价P3四、全文翻译P3五、词汇变式P4(一)考纲词汇词形转换P4(二)考纲词汇识词知意P4(三)高频短语积少成多P5(四)阅读理解单句填空变式P5(五)长难句分析P6六、三年真题P7(一)2023年新课标I卷阅读理解D篇P7(二)2022年新课标I卷阅读理解D篇P8(三)2021年新课标I卷阅读理解D篇P9七、满分策略（阅读理解说明文）P10八、阅读理解变式P12 变式一：生物多样性研究、发现、进展6篇P12变式二：阅读理解D篇35题变式（科普研究建议类）6篇P20一原题呈现阅读理解D篇关键词: 说明文;人与社会;社会科学研究方法研究;生物多样性; 科学探究精神;科学素养In the race to document the species on Earth before they go extinct, researchers and citizen scientists have collected billions of records. Today, most records of biodiversity are often in the form of photos, videos, and other digital records. Though they are useful for detecting shifts in the number and variety of species in an area, a new Stanford study has found that this type of record is not perfect.“With the rise of technology it is easy for people to make observation s of different species with the aid of a mobile application,” said Barnabas Daru, who is lead author of the study and assistant professor of biology in the Stanford School of Humanities and Sciences. “These observations now outnumber the primary data that comes from physical specimens(标本), and since we are increasingly using observational data to investigate how species are responding to global change, I wanted to know: Are they usable?”Using a global dataset of 1.9 billion records of plants, insects, birds, and animals, Daru and his team tested how well these data represent actual global biodiversity patterns.“We were particularly interested in exploring the aspects of sampling that tend to bias (使有偏差) data, like the greater likelihood of a citizen scientist to take a picture of a flowering plant instead of the grass right next to it,” said Daru.Their study revealed that the large number of observation-only records did not lead to better global coverage. Moreover, these data are biased and favor certain regions, time periods, and species. This makes sense because the people who get observational biodiversity data on mobile devices are often citizen scientists recording their encounters with species in areas nearby. These data are also biased toward certain species with attractive or eye-catching features.What can we do with the imperfect datasets of biodiversity?“Quite a lot,” Daru explained. “Biodiversity apps can use our study results to inform users of oversampled areas and lead them to places – and even species – that are not w ell-sampled. To improve the quality of observational data, biodiversity apps can also encourage users to have an expert confirm the identification of their uploaded image.”32. What do we know about the records of species collected now?A. They are becoming outdated.B. They are mostly in electronic form.C. They are limited in number.D. They are used for public exhibition.33. What does Daru’s study focus on?A. Threatened species.B. Physical specimens.C. Observational data.D. Mobile applications.34. What has led to the biases according to the study?A. Mistakes in data analysis.B. Poor quality of uploaded pictures.C. Improper way of sampling.D. Unreliable data collection devices.35. What is Daru’s suggestion for biodiversity apps?A. Review data from certain areas.B. Hire experts to check the records.C. Confirm the identity of the users.D. Give guidance to citizen scientists.二答案解析三专家评价考查关键能力，促进思维品质发展2024年高考英语全国卷继续加强内容和形式创新，优化试题设问角度和方式，增强试题的开放性和灵活性，引导学生进行独立思考和判断，培养逻辑思维能力、批判思维能力和创新思维能力。

2024年成人高考成考英语(高起专)复习试卷及解答参考一、语音知识（本大题有5小题，每小题2分，共10分）1、Choose the word that has the same pronunciation as the word “elephant.”A. elephantB. elephantC. elephantD. elephantAnswer: BExplanation: The word “elephant” is pronounced as /ˈɛl.ɪ.fɑːnt/. Among the options provided, “elephant” in option B is pronounced the same as the original word.2、Select the word that has the opposite meaning of “increase.”A. increaseB. increaseC. decreaseD. decreaseAnswer: CExplana tion: The word “increase” means to make larger or greater. The wordthat has the opposite meaning is “decrease,” which means to make smaller or less. Among the options, “decrease” in option C is the correct answer.3、The word “communicate” is pronounced as:A. /kəˈmjuːnɪkeɪt/B. /kəˈmjuːnɪkeɪt/C. /kəˈmjuːniːkeɪt/D. /kəˈmjuːniːkeɪt/Answer: AExplanation: The correct pronunciation of “communicate” is /kəˈmjuːnɪkeɪt/. The “c” in “communicate” is not hard, as it does not precede a double vowel.4、Which of the following words has the correct pronunciation?A. “Environment” - /ɪnˌvaɪrənˈmeɪnt/B. “Education” - /ˌɛdʒuˈkeɪʃən/C. “Imagine” - /ɪˈmædʒɪneɪt/D. “Compass” - /kəˈmæpəs/Answer: BExplanation: The correct pronunciation of “education” is /ˌɛdʒuˈkeɪʃən/. The “e” in “education” is long, as it is followed by a “g” which is silent. The other options have mispronounced vowels or consonants.5、The sentence “She always has a smile on her face” emphasizes that sheis always __________.A. cheerfulC. nervousD. sadAnswer: A. cheerfulExplanation: The word “always” in the sentence indicates a constant state or behavior. The phrase “has a smile on her face” suggests that she is in a good mood or happy, which is best described by the word “cheerful.” The other options do not accurately capture the positive connotation of the sentence.二、词汇与语法知识（本大题有15小题，每小题2分，共30分）1、Choose the correct word or phrase to complete the sentence below.The_______of the meeting was quite impressive.A. atmosphereB. audienceC. attendanceD. occasionAnswer: CExplanation: The correct answer is “attendance” because it refers to the number of people who were present at the meeting. The other options do not fit the context of the sentence.2、Select the word that does not belong in the following list.A. enthusiasticC. exhaustedD. alertAnswer: CExplanation: The word “exhausted” does not belong in the list because it is an adjective that describes someone who is very tired, whereas “enthusiastic,” “energetic,” and “alert” all describe someone who is full of energy or has a positive, watchful attitude.3、Choose the word that best completes the sentence.The teacher___________the students to be quiet during the examination.A. requestedB. suggestedC. orderedD. recommendedAnswer: C. orderedExplanation: The correct choice is “ordered” because it indicates a direct command or instruction from the teacher. The other options, while they could be used in some contexts, do not convey the same level of authority or necessity as “ordered” does in this sentence.4、Complete the sentence using the correct form of the verb in parentheses.If you________(be) more careful, you would not have made so many mistakes.A. areB. wereC. will beD. had beenAnswer: B. wereExplanation: The correct form of the verb to use in this sentence is “were,” which i s the past subjunctive form of “to be.” The sentence is expressing a hypothetical situation, which is a situation that is not real but is being considered for the sake of argument. The past subjunctive is used to describea condition that is not true but could have been or would have been.5、Choose the word that best completes the sentence.The professor___________the students’ questions eagerly.A. ignoredB. addressedC. neglectedD. overlookedAnswer: B. addressedExplanation: The correct word to complet e the sentence is “addressed,” which means to speak to or write to someone formally or officially. The professor is expected to address the students’ questions, not ignore, neglect, or overlook them.6、Complete the sentence with the correct form of the verb in parentheses.They___________(be) discussing the project when the meeting was called toorder.A. wereB. had beenC. have beenD. isAnswer: A. wereExplanation: The correct form of the verb is “were,” which is the past continuous tense. The sentence describes an action that was happening at a specific past time (when the meeting was called to order), so the past continuous tense is appropriate. The other options are incorrect because they do not match the context or the tense required.7、Choose the word that best completes the sentence.The teacher was surprised by the student’s_ability to understand complex concepts.A)surpriseB)surprisedC)surprisingD)surpriseablyAnswer: C) surprisingExplanation: The correct answer is “surprising” because it is the adjective form that describes the student’s ability. “Surprise” is a noun, “surprised” is the past participle form of the verb, and “surpriseably” is not a word.8、Complete the sentence with the correct form of the given verb in brackets.They (be) (not) aware of the changes that (take) place in the company last month.A)wereB)areC)wasD)beAnswer: A) wereExplanation: The correct answer is “were” because the subject “they” is plural, and the past perfect tense “had taken” indicates that the cha nges occurred before the awareness of them. Therefore, “were” is the correct past tense form of “be.”9.Choose the word that best completes the sentence.I can’t believe how____________changes have occurred in this small town over the past decade.A)numerousB)rapidC)suddenD)gradualAnswer: D) gradualExplanation: The sentence is describing changes that have occurred over a period of time, suggesting a process that was not immediate or extreme. “Gradual” fits this context best, indicating changes that happen slowly over time.10.Select the correct form of the verb to complete the following sentence.The professor___________us a detailed outline of the research project before the deadline.A)gaveB)has givenC)will giveD)is givingAnswer: B) has givenExplanation: The sentence implies that the action of giving the outline has already occurred before the deadline. The present perfect tense (“has given”) is used to describe actions that have a present relevance or result.11.Choose the correct word to complete the sentence:The manager was_about the new project, but the team was confident.A)apprehensiveB)optimisticC)indifferentD)enthusiasticAnswer: A) apprehensiveExplanation: The correct answer is “apprehensive” because it means feeling or showing anxiety or fear about something, which fits the context of the manager being concerned about the new project. The other options do not convey the same sense of worry or anxiety.12.Select the word that is closest in meaning to the underlined word:The teacher’s_appr oach to teaching made the subject much more engaging.A)traditionalB)innovativeC)passiveD)objectiveAnswer: B) innovativeExplanation: The underlined word “innovative” means introducing new methods or ideas. The sentence suggests that the teacher’s approach was different and made the subject more engaging. The word “traditional” would imply a more conventional method, “passive” would suggest a lack of interest, and “objective” would imply a neutral approach, none of which fit the context as well as “innovative.”13.Choose the word that best completes the sentence.The company’s new policy has been widely __________, with both positive and negative reactions.A. criticizedB. implementedC. supportedD. rejectedAnswer: B. implementedExplanation: The correct word here should reflect that the policy has been put into effect. “Implemented” means to carry out or put into effect, which fits the context. “Criticized” would imply there are negative reactions,“supported” would imply positive reactions, and “rejected” wo uld imply outright refusal, none of which fully capture the act of the policy being put into practice.14.Select the correct form of the verb to complete the sentence.She_______(go) to the market every morning, but now she has a car.A. used to goB. uses to goC. used goD. uses goAnswer: A. used to goExplanation: The correct phrase to use in this context is “used to” followed by the base form of the verb, which indicates a past habit or practice that has since changed. “Used to go” is the correc t past simple form that indicates a habit in the past. The other options are grammatically incorrect or do not convey the intended meaning.15.Choose the correct word or phrase to complete the sentence.The professor___________the students to study hard for the exam.A. advisedB. recommendedC. suggestedD. proposedAnswer: B. recommendedExplanation: The correct answer is “recommended” because it is the most appropriate word to express the professor’s advice. “Advised,” “suggested,” and “proposed” can also mean giving advice or suggestions, but “recommended”is often used in a more formal context, such as in an academic setting.三、完形填空（30分）Passage:In the small town of Willow Creek, there was once a charming old library that stood at the heart of the community. The library was a hub of learning and culture, where people of all ages would gather to read, discuss, and exchange ideas. The librarian, Mrs. Thompson, was known for her warm smile and vast knowledge of books. She had been working at the library for over 30 years and was deeply loved by everyone in the town.One day, the town’s mayor announced that the library was in danger of closing due to budget cuts. The community was shocked and immediately rallied to save their beloved library. They organized a series of events, including a book sale, a bake sale, and a benefit concert, to raise funds.The most successful event was the “Willow Creek Reads” program, where local authors were invited to read to the children and talk about their writing process. The children were excited and inspired, and the adults were reminded of the power of books to bring people together.As the days went by, more and more people began to donate books and moneyto the library. Mrs. Thompson was overwhelmed by the outpouring of support from the community. She knew that the library would not only survive but thrive.One evening, as Mrs. Thompson was organizing a new shelf of donated books, she noticed a mysterious note tucked inside one of the books. The note read, “To Mrs.Thompson, from the Friends of Willow Creek Library. We hope these books bring you joy and continue to inspire the community.”Mrs. Thompson smiled, knowing that the spirit of the library was alive and well.Blanks:1.The library in Willow Creek was a___________of learning and culture.2.Mrs. Thompson was___________for her warm smile and vast knowledge of books.3.The town’s mayor announced that the library was in___________due to budget cuts.4.The community___________to save their beloved library.5.The most successful event was the___________program.6.The children were___________and inspired by the local authors.7.The adults were___________of the power of books to bring people together.8.More and more people began to___________books and money to the library.9.Mrs. Thompson was___________by the outpouring of support from the community.10.The note was a___________from the Friends of Willow Creek Library.11.Mrs. Thompson smiled, knowing that the spirit of the librarywas___________and well.Questions:11.What was the note a___________from the Friends of Willow Creek Library?A)InvitationB)ComplaintC)Thank youD)ApologyAnswer:C) Thank you四、阅读理解（本部分有5大题，每大题9分，共45分）第一题Read the following passage and answer the questions that follow.The Internet has revolutionized the way we communicate, access information, and conduct business. With just a few clicks, we can connect with people from all over the world, access a vast amount of information, and even conduct transactions online. However, along with these benefits, the Internet has also brought about various challenges and risks. One of the most significant risks is the potential for cybercrime, which includes hacking, identity theft, and phishing.1.What is one of the major risks associated with the use of the Internet?A. Improved communicationB. Access to a vast amount of informationC. Potential for cybercrimeD. Increased business opportunities2.What are some examples of cybercrimes mentioned in the passage?A. Hacking, identity theft, and phishingB. Improved communication and access to informationC. Increased business opportunitiesD. Reduced need for physical interaction3.How does the Internet impact the way we conduct business?A. It reduces the need for physical interactionB. It increases the potential for cybercrimeC. It provides a platform for global communication and transactionsD. It eliminates the need for traditional banking and financial servicesAnswers:1.C2.A3.C第二题Passage:The rapid development of technology has greatly influenced the way people communicate. Social media platforms have become an integral part of daily life,allowing individuals to connect with others across the globe. However, this shift in communication has raised concerns about the impact on face-to-face interactions and the potential loss of traditional social skills.One of the most popular social media platforms is Instagram, which is known for its focus on visual content. Users can share photos, videos, and stories, and follow others who share similar interests. While Instagram can be a great way to stay connected with friends and discover new things, it also has its downsides.A recent study found that excessive use of Instagram can lead to feelings of loneliness and depression. The constant comparison with others’ seemingly perfect lives can create a sense of inadequacy. Additionally, the platform’s algorithm can create a filter bubble, where users are only exposed to content that aligns with their existing beliefs and interests, thus limiting their exposure to diverse perspectives.Despite these concerns, many people find Instagram to be a valuable tool for networking and personal growth. It can provide a platform for artists, writers, and entrepreneurs to showcase their work and connect with potential audiences. Moreover, it can be a source of inspiration and motivation, as users are exposed to the achievements and stories of others.Questions:1、What is the main topic of the passage?A) The benefits of using social media platforms.B) The negative effects of Instagram on social interactions.C) The history of social media platforms.D) The role of technology in modern communication.2、Which of the following is NOT mentioned as a potential negative effect of using Instagram?A) Feelings of inadequacy.B) Limited exposure to diverse perspectives.C) Improved communication skills.D) Increased feelings of loneliness and depression.3、What is the author’s attitude towards Instagram?A) Highly critical.B) Indifferent.C) Positive and supportive.D) Ambiguous.Answers:1、B) The negative effects of Instagram on social interactions.2、C) Improved communication skills.3、D) Ambiguous.第三题Reading Passage:In the small town of Greenfield, there was a long-standing tradition of the annual Greenfield Festival. The festival, which took place every autumn, broughttogether local artists, musicians, and performers from around the region. It was a time for celebration, a showcase of local talent, and a chance for the community to come together and enjoy the arts.One of the highlights of the festival was the “Greenfield Talent Show,” where local residents could audition to perform. This year, the talent show had a special twist: the winner would receive a scholarship to study music at a prestigious music school in the nearby city of Bluewater.Word Count: 102Questions:1、What is the main purpose of the Greenfield Festival?A) To promote tourism in GreenfieldB) To bring the community together and celebrate local artsC) To raise funds for charityD) To promote agricultural products2、Which event at the festival was of particular interest to this year’s participants?A) The art exhibitionB) The music concertC) The Greenfield Talent ShowD) The local craft fair3、What reward did the winner of the Greenfield Talent Show receive?A) A cash prizeB) A trip to the nearby cityC) A scholarship to study musicD) A trophyAnswers:1、B) To bring the community together and celebrate local arts2、C) The Greenfield Talent Show3、C) A scholarship to study music第四题Reading ComprehensionRead the following passage and answer the questions that follow.The rise of e-commerce has revolutionized the way people shop and has had a significant impact on traditional brick-and-mortar stores. Online shopping has become increasingly popular due to its convenience and the vast variety of products available. However, this shift has also brought about challenges and changes in the retail industry.One of the main advantages of e-commerce is the convenience it offers. Customers can shop from the comfort of their own homes at any time of the day or night. This eliminates the need to travel to physical stores and wait in long queues. Additionally, online platforms often provide detailed product descriptions, customer reviews, and even virtual try-ons, which can help customers make more informed purchasing decisions.Despite these benefits, e-commerce has also presented challenges fortraditional retailers. Many have had to adapt to the changing landscape by investing in their online presence and offering competitive pricing and customer service. However, some have struggled to keep up and have been forced to close their doors.The retail industry is also witnessing a shift in consumer behavior. Customers are becoming more environmentally conscious and are increasingly looking for sustainable and ethical products. This has led to a rise ineco-friendly shopping options and a decline in demand for fast fashion.1.What is the main advantage of e-commerce mentioned in the passage?A) Competitive pricingB) ConvenienceC) Eco-friendly optionsD) Detailed product reviews2.How has e-commerce affected traditional brick-and-mortar stores?A) They have become more profitable.B) They have had to adapt and invest in online presence.C) They have seen a significant increase in foot traffic.D) They have closed down due to increased competition.3.What is the trend in consumer behavior mentioned in the passage?A) Customers are looking for more affordable products.B) Customers are becoming more environmentally conscious.C) Customers are preferring fast fashion over sustainable options.D) Customers are no longer interested in online shopping.Answers:1.B) Convenience2.B) They have had to adapt and invest in online presence.3.B) Customers are becoming more environmentally conscious.第五题Read the following passage and answer the questions that follow.In recent years, there has been a growing interest in online education. This shift is primarily due to the convenience and flexibility it offers to students. Online courses allow individuals to learn at their own pace, from any location, and often at a lower cost compared to traditional in-person classes. However, despite these advantages, online learning also comes with its own set of challenges.One of the main concerns is the potential for reduced social interaction. In traditional classrooms, students have the opportunity to engage with their peers and professors, which can enhance their learning experience. Online students, on the other hand, may feel isolated and disconnected from the academic community. This can lead to a lack of motivation and engagement in the course material.Another challenge is the need for self-discipline. Online courses require students to be self-motivated and organized. Without the structure of a traditional classroom, students must set their own schedules and manage their time effectively. This can be difficult for some individuals, especially thosewho are accustomed to the routine of attending classes on campus.Despite these challenges, many online learners find that the benefits outweigh the drawbacks. They appreciate the ability to work around their other commitments, such as full-time jobs or family responsibilities. Additionally, online courses often provide access to a wider range of resources and expertise than traditional courses.1.The primary reason for the growing interest in online education is:a) the opportunity for social interactionb) the flexibility and convenience it offersc) the lower cost compared to traditional in-person classesd) the access to a wider range of resources2.What is one of the main concerns mentioned about online learning?a) The convenience of learning at one’s own paceb) The potential for reduced social interactionc) The lower cost of online coursesd) The increased access to expertise3.According to the passage, which of the following is a challenge for online learners?a) The ease of engaging with peers and professorsb) The need for self-discipline and organizationc) The lower cost of online coursesd) The ability to work around other commitmentsAnswers:1.b) the flexibility and convenience it offers2.b) The potential for reduced social interaction3.b) The need for self-discipline and organization五、补全对话（本大题有5小题，每小题3分，共15分）第一题A: Excuse me, could you help me with some English vocabulary?B: Sure, I’d be happy to. What would you like to know about?A: I need to expand my vocabulary for the college entrance exam. Can you suggest some useful words for an “Adult Higher Education” (AHLE) English test?B: Absolutely! Here are a few words and phrases that are often included in such exams:1.(______) - a higher level of education beyond high school.2.(______) - a system of post-secondary education that allows working adults to earn degrees.3.(______) - a person who is studying or has studied at a college or university.4.(______) - a course or program of study that leads to a degree or certification.5.(______) - a test taken by students to gain admission to a college or university.A: Great, thanks! What should I write in the blank spaces?B:1.(______) - A higher level of education beyond high school.2.(______) - A system of post-secondary education that allows working adults to earn degrees.3.(______) - A person who is studying or has studied at a college or university.4.(______) - A course or program of study that leads to a degree or certification.5.(______) - A test taken by students to gain admission to a college or university.答案：1.Degree2.Adult Higher Education (AHLE)3.College student4.Curriculum5.Admission test解析：1.Degree - This word is used to describe a higher level of education, which is a key concept in the context of college education.2.Adult Higher Education (AHLE) - This specific term refers to the system that caters to working adults who wish to pursue further education.3.College student - This phrase describes someone who is currently or has been enrolled in a college or university.4.Curriculum - This word refers to the courses or program of study that an educational institution offers.5.Admission test - This term refers to the test that students must take to be admitted to a college or university, which is a common requirement for higher education.第二题1.A: I’m sorry, but I can’t help you with that right now.B: Why not?A: Because I’m currently in a meeting.B: Oh, I see. Well, can I leave you a message?A: Certainly, you can.B: Thank you. I’ll just write down my number and call you back after the meeting.A: That sounds good.B: Is there anything specific you need help with?A: Yes, actually. I need some information about the new software package our company is considering.B: Of course. Let me check if I have that information available.A: Alright, take your time.B: I should be able to find it for you. Just a moment, please.A: No problem.B: There we go. I have the information you need.A: Great, thanks. Can you send it to my email?B: Absolutely. I’ll send it over right now.A: Perfect. I appreciate your help.B: You’re welcome. Feel free to call back if you need anything else.A: Will do. Have a good meeting.B: You too. Goodbye.1.A: I’m sorry, but I can’t help you with that right now.B: Why not?A: Because I’m currently in a meeting.B: Oh, I see. Well, can I leave you a message?A: Certainly, you can.B: Thank you. I’ll just write down my number and call you back after the meeting.A: That sounds good.B: Is there anything specific you need help with?A: Yes, actually. I need some information about the new software package our company is considering.B: Of course. Let me check if I have that information available.A: Alright, take your time.B: I should be able to find it for you. Just a moment, please.A: No problem.B: There we go. I have the information you need.A: Great, thanks. Can you send it to my email?B: Absolutely. I’ll send it over right now.A: Perfect. I appreciate your help.B: You’re welc ome. Feel free to call back if you need anything else.A: Will do. Have a good meeting.B: You too. Goodbye.答案：解析：The correct continuation of the dialogue is B because it maintains the context of the original message and provides a logical progression of the conversation. It addresses the initial reason for the inability to assist and then moves on to offering a solution (leaving a message) and asking for further details about the assistance needed. The dialogue then proceeds with the person finding the information, offering to send it via email, and concluding with a friendly farewell.第三题A: Excuse me, I’m looking for the English section of the Adult College Entrance Examination. Can you help me?B: Sure, follow me. You need to go to the second floor and then turn right. The English section is located in Room 202.A: Oh, okay. Thank you. By the way, what time does the exam start?B: The exam will begin at 9:00 a.m. sharp. Make sure you arrive 30 minutes early to get settled.A: Got it. I’ll be there on t ime. One more thing, is there a specific roomfor the English exam?B: Yes, it’s Room 202 as well. You’ll see a sign indicating the English section.A: Perfect. Thanks again for your help.B: You’re welcome. Good luck with your exam!Answer:B: Yes, it’s Room 202 as well. You’ll see a sign indicating the English section.Explanation:In this dialogue, the student is asking for directions to the English section of the exam. The answer to the question is found in the response by the staff member. They confirm that the English exam is held in Room 202, as indicated by a sign, providing clear information to the student.第四题A: Excuse me, I seem to have misplaced my calculator. Can you help me find it?B: Sure, where do you think you might have left it?A: I was working on this problem for our math class, and I think I might have left it on the desk.B: Okay, let’s check the desk first. Is this the one you’re looking for?A: No, that’s not it. It was smaller and black.B: Alright, let’s look over there by the window. Do you see anything that。

八年级科技前沿英语阅读理解25题1<背景文章>Artificial intelligence (AI) has been making remarkable strides in the medical field in recent years. AI - powered systems are being increasingly utilized in various aspects of healthcare, bringing about significant improvements and new possibilities.One of the most prominent applications of AI in medicine is in disease diagnosis. AI algorithms can analyze vast amounts of medical data, such as patient symptoms, medical histories, and test results. For example, deep - learning algorithms can scan X - rays, CT scans, and MRIs to detect early signs of diseases like cancer, pneumonia, or heart diseases. These algorithms can often spot minute details that might be overlooked by human doctors, thus enabling earlier and more accurate diagnoses.In the realm of drug development, AI also plays a crucial role. It can accelerate the process by predicting how different molecules will interact with the human body. AI - based models can sift through thousands of potential drug candidates in a short time, identifying those with the highest probability of success. This not only saves time but also reduces the cost associated with traditional trial - and - error methods in drug research.Medical robots are another area where AI is making an impact.Surgical robots, for instance, can be guided by AI systems to perform complex surgeries with greater precision. These robots can filter out the natural tremors of a surgeon's hand, allowing for more delicate and accurate incisions. Additionally, there are robots designed to assist in patient care, such as those that can help patients with limited mobility to move around or perform simple tasks.However, the application of AI in medicine also faces some challenges. Issues like data privacy, algorithmic bias, and the need for regulatory approval are important considerations. But overall, the potential of AI to transform the medical field is vast and holds great promise for the future of healthcare.1. What is one of the main applications of AI in the medical field according to the article?A. Designing hospital buildings.B. Disease diagnosis.C. Training medical students.D. Managing hospital finances.答案：B。

Title Example42g—One-and two-level mediation models(multilevel)Description Remarks and examples References Also seeDescriptionTo demonstrate linear mediation models,we use the following data:.use https:///data/r18/gsem_multmed(Fictional job-performance data).summarizeVariable Obs Mean Std.dev.Min Maxbranch1,5003821.65593175support1,500.0084667.5058316-1.6 1.8satis1,500.0212.6087235-1.62perform1,500 5.005317.8949845 2.350228.084294.notes_dta:1.Fictional data on job performance,job satisfaction,and perceivedsupport from managers for1,500sales employees of a large departmentstore in75locations.2.Variable support is average of Likert-scale questions,each questionscored from-2to2.3.Variable satis is average of Likert-scale questions,each question scoredfrom-2to2.4.Variable perform is job performance measured on continuous scale.See Structural models1:Linear regression and Multilevel mixed-effects models in[SEM]Intro5 for background.Remarks and examples Remarks are presented under the following headings:One-level model with semOne-level model with gsemTwo-level model with gsemFitting the models with the BuilderOne-level model with semYou canfit single-level mediation models with sem or gsem.You will be better off using sem because then you can use estat teffects afterward to compute indirect and total effects.12Example42g—One-and two-level mediation models(multilevel)The model we wish tofit is the simplest form of a mediation model,namely,We are interested in the effect of managerial support on job performance,but we suspect a portion of the effect might be mediated through job satisfaction.In traditional mediation analysis,the model would befit by a series of linear regression models as described in Baron and Kenny(1986).That approach is sufficient because the errors are not correlated.The advantage of using structural equation modeling is that you canfit a single model and estimate the indirect and total effects,and you can embed the simple mediation model in a larger model and even use latent variables to measure any piece of the mediation model.Tofit this model with the command syntax,we type.sem(perform<-satis support)(satis<-support)Endogenous variablesObserved:perform satisExogenous variablesObserved:supportFitting target model:Iteration0:Log likelihood=-3779.9224Iteration1:Log likelihood=-3779.9224Structural equation model Number of obs=1,500Estimation method:mlLog likelihood=-3779.9224OIMCoefficient std.err.z P>|z|[95%conf.interval] Structuralperformsatis.8984401.025190335.670.000.849068.9478123support.6161077.030314320.320.000.5566927.6755227_cons 4.981054.0150589330.770.000 4.951539 5.010569 satissupport.2288945.03050477.500.000.1691064.2886826_cons.019262.0154273 1.250.212-.0109749.0494989 var(e.perf~m).3397087.0124044.3162461.364912var(e.satis).3569007.0130322.3322507.3833795LR test of model vs.saturated:chi2(0)=0.00Prob>chi2=.Example42g—One-and two-level mediation models(multilevel)3Notes:1.The direct effect of managerial support on job performance is measured by perform<-supportand is estimated to be0.6161.The effect is small albeit highly statistically significant.The standard deviations of performance and support are0.89and0.51.A one standard deviation increase in support improves performance by a third of a standard deviation.2.The direct effect of job satisfaction on job performance is measured by perform<-satis andis estimated to be0.8984.That also is a moderate effect,practically speaking,and is highly statistically significant.3.The effect of managerial support on job satisfaction is measured by satis<-support and ispractically small but statistically significant.4.What is the total effect of managerial support on performance?It is the direct effect(0.6161)plus the indirect effect of support on satisfaction on performance(0.2289×0.8984=0.2056), meaning the total effect is0.8217.It would be desirable to put a standard error on that,but that’s more work.We can use estat teffects after estimation to obtain the total effect and its standard error: .estat teffectsDirect effectsOIMCoefficient std.err.z P>|z|[95%conf.interval] Structuralperformsatis.8984401.025190335.670.000.849068.9478123support.6161077.030314320.320.000.5566927.6755227 satissupport.2288945.03050477.500.000.1691064.2886826 Indirect effectsOIMCoefficient std.err.z P>|z|[95%conf.interval] Structuralperformsatis0(no path)support.205648.02800667.340.000.150756.26054 satissupport0(no path)Total effectsOIMCoefficient std.err.z P>|z|[95%conf.interval] Structuralperformsatis.8984401.025190335.670.000.849068.9478123support.8217557.040457920.310.000.7424597.9010516 satissupport.2288945.03050477.500.000.1691064.28868264Example42g—One-and two-level mediation models(multilevel)One-level model with gsemWe canfit the same model with gsem.The command is the same except that we substitute gsem for sem,and results are identical:.gsem(perform<-satis support)(satis<-support)Iteration0:Log likelihood=-2674.3421Iteration1:Log likelihood=-2674.3421(backed up)Generalized structural equation model Number of obs=1,500Response:performFamily:GaussianLink:IdentityResponse:satisFamily:GaussianLink:IdentityLog likelihood=-2674.3421Coefficient Std.err.z P>|z|[95%conf.interval] performsatis.8984401.025190335.670.000.849068.9478123support.6161077.030314320.320.000.5566927.6755227_cons 4.981054.0150589330.770.000 4.951539 5.010569 satissupport.2288945.03050477.500.000.1691064.2886826_cons.019262.0154273 1.250.212-.0109749.0494989 var(e.perf~m).3397087.0124044.3162461.364912var(e.satis).3569007.0130322.3322507.3833795 After gsem,however,we cannot use estat teffects:.estat teffectsestat teffects not validr(321);We can,however,calculate the indirect and total effects for ourselves and obtain the standard error by using nlcom.Referring back to note4of the previous section,the formula for the indirect effect and total effects areindirect effect=β1β4total effect=β2+β1β4whereβ1=path coefficient for perform<-satisβ4=path coefficient for satis<-supportβ2=path coefficient for perform<-support It turns out that we can access the coefficients by typingβ1=b[perform:satis]β4=b[satis:support]β2=b[perform:support]Example42g—One-and two-level mediation models(multilevel)5which is most easily revealed by typing.gsem,coeflegend(output omitted)Thus we can obtain the indirect effect by typing.nlcom_b[perform:satis]*_b[satis:support]_nl_1:_b[perform:satis]*_b[satis:support]Coefficient Std.err.z P>|z|[95%conf.interval] _nl_1.205648.02800667.340.000.150756.26054and we can obtain the total effect by typing.nlcom_b[perform:support]+_b[perform:satis]*_b[satis:support]_nl_1:_b[perform:support]+_b[perform:satis]*_b[satis:support]Coefficient Std.err.z P>|z|[95%conf.interval]_nl_1.8217557.040457920.310.000.7424597.9010516Two-level model with gsemIt may be easier to use sem rather than gsem forfitting single-level models,but if you want tofit multilevel models,you must use gsem.A variation on the model we justfit isIn this model,we include a random intercept in each equation at the branch(individual store) level.The model above is one of many variations on two-level mediation models;see Krull and MacKinnon(2001)for an introduction to multilevel mediation models,and see Preacher,Zyphur,and Zhang(2010)for a discussion offitting these models with structural equation modeling.6Example42g—One-and two-level mediation models(multilevel)Tofit this model with the command syntax,we type.gsem(perform<-satis support M1[branch])(satis<-support M2[branch]),>cov(M1[branch]*M2[branch]@0)Fitting fixed-effects model:Iteration0:Log likelihood=-2674.3421Iteration1:Log likelihood=-2674.3421Refining starting values:Grid node0:Log likelihood=-2132.1613Fitting full model:Iteration0:Log likelihood=-2132.1613(not concave)Iteration1:Log likelihood=-1801.3155Iteration2:Log likelihood=-1769.6421Iteration3:Log likelihood=-1705.1282Iteration4:Log likelihood=-1703.746Iteration5:Log likelihood=-1703.7141Iteration6:Log likelihood=-1703.714Generalized structural equation model Number of obs=1,500Response:performFamily:GaussianLink:IdentityResponse:satisFamily:GaussianLink:IdentityLog likelihood=-1703.714(1)[perform]M1[branch]=1(2)[satis]M2[branch]=1Coefficient Std.err.z P>|z|[95%conf.interval] performsatis.604264.033639817.960.000.5383313.6701968support.6981525.025043227.880.000.6490687.7472364 M1[branch]1(constrained)_cons 4.986596.0489465101.880.000 4.890663 5.082529 satissupport.2692633.017964914.990.000.2340528.3044739 M2[branch]1(constrained)_cons.0189202.05708680.330.740-.0929678.1308083var(M1[branch]).1695962.0302866.119511.2406713var(M2[branch]).2384738.0399154.1717781.3310652var(e.perf~m).201053.0075451.1867957.2163985var(e.satis).1188436.0044523.1104299.1278983Notes:1.In One-level model with sem above,we measured the direct effects on job performance of jobsatisfaction and managerial support as0.8984and0.6161.Now the direct effects are0.6043and0.6982.Example42g—One-and two-level mediation models(multilevel)72.We can calculate the indirect and total effects just as we did in the previous section,whichwe will do below.We mentioned earlier that there are other variations of two-level mediation models,and how you calculate total effects depends on the model chosen.In this case,the indirect effect is.nlcom_b[perform:satis]*_b[satis:support]_nl_1:_b[perform:satis]*_b[satis:support]Coefficient Std.err.z P>|z|[95%conf.interval]_nl_1.1627062.014138211.510.000.1349958.1904165and the total effect is.nlcom_b[perform:support]+_b[perform:satis]*_b[satis:support]_nl_1:_b[perform:support]+_b[perform:satis]*_b[satis:support]Coefficient Std.err.z P>|z|[95%conf.interval]_nl_1.8608587.025750133.430.000.8103894.911328Fitting the models with the BuilderUse the diagram in One-level model with sem above for reference.1.Open the dataset.In the Command window,type.use https:///data/r18/gsem_multmed2.Open a new Builder diagram.Select menu item Statistics>SEM(structural equation modeling)>Model building and estimation.3.Create a regression component for the perform outcome.Select the Add regression component tool,,and then click in the center of the diagram.In the resulting dialog box,a.select perform in the Dependent variable control;b.select support with the Independent variables control;c.select Left in the Independent variables’direction control;d.click on OK.e the Select tool,,to select only the perform rectangle,and drag it to the right toincrease the distance between the rectangles.(You can hold the Shift key while dragging toensure that the movement is directly to the right.)4.Create the mediating variable.a.Select the Add observed variable tool,,and then click in the diagram above the pathfrom support to perform.b.In the Contextual Toolbar,select satis with the Variable control.8Example42g—One-and two-level mediation models(multilevel)5.Create the paths to and from the mediating variable.a.Select the Add path tool,.b.Click in the upper right of the support rectangle(it will highlight when you hover overit),and drag a path to the lower left of the satis rectangle(it will highlight when you can release to connect the path).c.Continuing with the tool,draw a path from the lower right of the satis rectangle tothe upper left of the perform rectangle.6.Clean up the direction of the error term.We want the error for each of the endogenous variables to be to the right of the rectangle.The error for satis may have been created in another direction.If so,a.choose the Select tool,;b.click in the satis rectangle;c.click on one of the Error rotation buttons,,in the Contextual Toolbar until the erroris to the right of the rectangle.7.Clean up the location of the paths.If you do not like where the paths have been connected to the rectangles,use the Select tool, ,to click on the path,and then simply click on where it connects to a rectangle and drag the endpoint.8.Estimate.Click on the Estimate button,,in the Standard Toolbar,and then click on OK in the resulting SEM estimation options dialog box.9.Tofit the model in Two-level model with gsem,continue with the previous diagram,and put thebuilder in gsem mode by clicking on the button.10.Create the multilevel latent variable corresponding to the random intercept for satis.a.Select the Add multilevel latent variable tool,,and click above the rectangle for satis.b.In the Contextual Toolbar,click on the button.c.Select the nesting level and nesting variable by selecting2from the Nesting depth controland selecting branch>Observations in the next control.d.Specify M1as the Base name.e.Click on OK.11.Create the multilevel latent variable corresponding to the random intercept for perform.a.Select the Add multilevel latent variable tool,,and click above the rectangle for satisand to the right of the branch1double oval.b.In the Contextual Toolbar,click on the button.c.Select the nesting level and nesting variable by selecting2from the Nesting depth controland selecting branch>Observations in the next control.d.Specify M2as the Base name.e.Click on OK.Example42g—One-and two-level mediation models(multilevel)9 12.Draw paths from the multilevel latent variables to their corresponding endogenous variables.a.Select the Add pathtool,.b.Click in the bottom of the branch1double oval,and drag a path to the top of the satisrectangle.c.Continuing withthe tool,click in the bottom of the branch2double oval,and drag apath to the top of the perform rectangle.13.Estimate again.Click on the Estimatebutton,,in the Standard Toolbar,and then click on OK in the resultingGSEM estimation options dialog box.You can open a completed diagram for thefirst model in the Builder by typing.webgetsem sem_medYou can open a completed diagram for the second model in the Builder by typing .webgetsem gsem_mlmedReferencesBaron,R.M.,and D.A.Kenny.1986.The moderator–mediator variable distinction in social psychological research: Conceptual,strategic,and statistical considerations.Journal of Personality and Social Psychology51:1173–1182.https:///10.1037//0022-3514.51.6.1173.Krull,J.L.,and D.P.MacKinnon.2001.Multilevel modeling of individual and group level mediated effects.Multivariate Behavorial Research36:249–277.https:///10.1207/S1*******MBR360206.Preacher,K.J.,M.J.Zyphur,and Z.Zhang.2010.A general multilevel SEM framework for assessing multilevel mediation.Psychological Methods15:209–233.https:///10.1037/a0020141.Also see[SEM]Example38g—Random-intercept and random-slope models(multilevel)[SEM]Intro5—Tour of models[SEM]gsem—Generalized structural equation model estimation command[CAUSAL]mediate—Causal mediation analysisStata,Stata Press,and Mata are registered trademarks of StataCorp LLC.Stata andStata Press are registered trademarks with the World Intellectual Property Organizationof the United Nations.Other brand and product names are registered trademarks ortrademarks of their respective companies.Copyright c 1985–2023StataCorp LLC,College Station,TX,USA.All rights reserved.®。

On the Interactions of Light GravitinosT.E.Clark1,Taekoon Lee2,S.T.Love3,Guo-Hong Wu4Department of PhysicsPurdue UniversityWest Lafayette,IN47907-1396AbstractIn models of spontaneously broken supersymmetry,certain light gravitino processes are governed by the coupling of its Goldstino components.The rules for constructing SUSY and gauge invariant actions involving the Gold-stino couplings to matter and gaugefields are presented.The explicit oper-ator construction is found to be at variance with some previously reported claims.A phenomenological consequence arising from light gravitino inter-actions in supernova is reexamined and scrutinized.1e-mail address:clark@2e-mail address:tlee@3e-mail address:love@4e-mail address:wu@1In the supergravity theories obtained from gauging a spontaneously bro-ken global N=1supersymmetry(SUSY),the Nambu-Goldstone fermion, the Goldstino[1,2],provides the helicity±1degrees of freedom needed to render the spin3gravitino massive through the super-Higgs mechanism.For a light gravitino,the high energy(well above the gravitino mass)interactions of these helicity±1modes with matter will be enhanced according to the su-persymmetric version of the equivalence theorem[3].The effective action de-scribing such interactions can then be constructed using the properties of the Goldstinofields.Currently studied gauge mediated supersymmetry breaking models[4]provide a realization of this scenario as do certain no-scale super-gravity models[5].In the gauge mediated case,the SUSY is dynamically broken in a hidden sector of the theory by means of gauge interactions re-sulting in a hidden sector Goldstinofield.The spontaneous breaking is then mediated to the minimal supersymmetric standard model(MSSM)via radia-tive corrections in the standard model gauge interactions involving messenger fields which carry standard model vector representations.In such models,the supergravity contributions to the SUSY breaking mass splittings are small compared to these gauge mediated contributions.Being a gauge singlet,the gravitino mass arises only from the gravitational interaction and is thus farsmaller than the scale √,where F is the Goldstino decay constant.More-2over,since the gravitino is the lightest of all hidden and messenger sector degrees of freedom,the spontaneously broken SUSY can be accurately de-scribed via a non-linear realization.Such a non-linear realization of SUSY on the Goldstinofields was originally constructed by Volkov and Akulov[1].The leading term in a momentum expansion of the effective action de-scribing the Goldstino self-dynamics at energy scales below √4πF is uniquelyfixed by the Volkov-Akulov effective Lagrangian[1]which takes the formL AV=−F 22det A.(1)Here the Volkov-Akulov vierbein is defined as Aµν=δνµ+iF2λ↔∂µσν¯λ,withλ(¯λ)the Goldstino Weyl spinorfield.This effective Lagrangian pro-vides a valid description of the Goldstino self interactions independent of the particular(non-perturbative)mechanism by which the SUSY is dynam-ically broken.The supersymmetry transformations are nonlinearly realized on the Goldstinofields asδQ(ξ,¯ξ)λα=Fξα+Λρ∂ρλα;δQ(ξ,¯ξ)¯λ˙α= F¯ξ˙α+Λρ∂ρ¯λ˙α,whereξα,¯ξ˙αare Weyl spinor SUSY transformation param-eters andΛρ≡−i Fλσρ¯ξ−ξσρ¯λis a Goldstinofield dependent translationvector.Since the Volkov-Akulov Lagrangian transforms as the total diver-genceδQ(ξ,¯ξ)L AV=∂ρ(ΛρL AV),the associated action I AV= d4x L AV is SUSY invariant.The supersymmetry algebra can also be nonlinearly realized on the matter3(non-Goldstino)fields,generically denoted byφi,where i can represent any Lorentz or internal symmetry labels,asδQ(ξ,¯ξ)φi=Λρ∂ρφi.(2) This is referred to as the standard realization[6]-[9].It can be used,along with space-time translations,to readily establish the SUSY algebra.Under the non-linear SUSY standard realization,the derivative of a matterfield transforms asδQ(ξ,¯ξ)(∂νφi)=Λρ∂ρ(∂νφi)+(∂νΛρ)(∂ρφi).In order to elim-inate the second term on the right hand side and thus restore the standard SUSY realization,a SUSY covariant derivative is introduced and defined so as to transform analogously toφi.To achieve this,we use the transformation property of the Volkov-Akulov vierbein and define the non-linearly realized SUSY covariant derivative[9]Dµφi=(A−1)µν∂νφi,(3) which varies according to the standard realization of SUSY:δQ(ξ,¯ξ)(Dµφi)=Λρ∂ρ(Dµφi).Any realization of the SUSY transformations can be converted to the standard realization.In particular,consider the gauge covariant derivative,(Dµφ)i≡∂µφi+T a ij A aµφj,(4)4with a=1,2,...,Dim G.We seek a SUSY and gauge covariant deriva-tive(Dµφ)i,which transforms as the SUSY standard ing the Volkov-Akulov vierbein,we define(Dµφ)i≡(A−1)µν(Dνφ)i,(5) which has the desired transformation property,δQ(ξ,¯ξ)(Dµφ)i=Λρ∂ρ(Dµφ)i, provided the vector potential has the SUSY transformationδQ(ξ,¯ξ)Aµ≡Λρ∂ρAµ+∂µΛρAρ.Alternatively,we can introduce a redefined gaugefieldV aµ≡(A−1)µνA aν,(6) which itself transforms as the standard realization,δQ(ξ,¯ξ)V aµ=Λρ∂ρV aµ, and in terms of which the standard realization SUSY and gauge covariant derivative then takes the form(Dµφ)i≡(A−1)µν∂νφi+T a ij V aµφj.(7) Under gauge transformations parameterized byωa,the original gaugefield varies asδG(ω)A aµ=(Dµω)a=∂µωa+gf abc A bµωc,while the redefinedgaugefield V aµhas the Goldstino dependent transformation:δG(ω)V aµ= (A−1)µν(Dνω)a.For all realizations,the gauge transformation and SUSY transformation commutator yields a gauge variation with a SUSY trans-formed value of the gauge transformation parameter,δG(ω),δQ(ξ,¯ξ)=δG(Λρ∂ρω−δQ(ξ,¯ξ)ω).(8) 5If we further require the local gauge transformation parameter to also trans-form under the standard realization so thatδQ(ξ,¯ξ)ωa=Λρ∂ρωa,then the gauge and SUSY transformations commute.In order to construct an invariant kinetic energy term for the gaugefields, it is convenient for the gauge covariant anti-symmetric tensorfield strength to also be brought into the standard realization.The usualfield strengthF a αβ=∂αA aβ−∂βA aα+if abc A bαA cβvaries under SUSY transformations asδQ(ξ,¯ξ)F aµν=Λρ∂ρF aµν+∂µΛρF aρν+∂νΛρF aµρ.A standard realization of thegauge covariantfield strength tensor,F aµν,can be then defined asF aµν=(A−1)µα(A−1)νβF aαβ,(9) so thatδQ(ξ,¯ξ)F aµν=Λρ∂ρF aµν.These standard realization building blocks consisting of the gauge singlet Goldstino SUSY covariant derivatives,Dµλ,Dµ¯λ,the matterfields,φi,their SUSY-gauge covariant derivatives,Dµφi,and thefield strength tensor,F aµν, along with their higher covariant derivatives can be combined to make SUSY and gauge invariant actions.These invariant action terms then dictate the couplings of the Goldstino which,in general,carries the residual consequences of the spontaneously broken supersymmetry.A generic SUSY and gauge invariant action can be constructed[9]asI eff=d4x detA L eff(Dµλ,Dµ¯λ,φi,Dµφi,Fµν)(10)6where L effis any gauge invariant function of the standard realization basic building ing the nonlinear SUSY transformationsδQ(ξ,¯ξ)detA=∂ρ(ΛρdetA)andδQ(ξ,¯ξ)L eff=Λρ∂ρL eff,it follows thatδQ(ξ,¯ξ)I eff=0.It proves convenient to catalog the terms in the effective Lagranian,L eff, by an expansion in the number of Goldstinofields which appear when covari-ant derivatives are replaced by ordinary derivatives and the Volkov-Akulov vierbein appearing in the standard realizationfield strengths are set to unity. So doing,we expandL eff=L(0)+L(1)+L(2)+···,(11)where the subscript n on L(n)denotes that each independent SUSY invariant operator in that set begins with n Goldstinofields.L(0)consists of all gauge and SUSY invariant operators made only from light matterfields and their SUSY covariant derivatives.Any Goldstinofield appearing in L(0)arises only from higher dimension terms in the matter covariant derivatives and/or thefield strength tensor.Taking the light non-Goldstinofields to be those of the MSSM and retaining terms through mass dimension4,then L(0)is well approximated by the Lagrangian of the mini-mal supersymmetric standard model which includes the soft SUSY breaking terms,but in which all derivatives have been replaced by SUSY covariant ones and thefield strength tensor replaced by the standard realizationfield7strength:L(0)=L MSSM(φ,Dµφ,Fµν).(12) Note that the coefficients of these terms arefixed by the normalization of the gauge and matterfields,their masses and self-couplings;that is,the normalization of the Goldstino independent Lagrangian.The L(1)terms in the effective Lagrangian begin with direct coupling of one Goldstino covariant derivative to the non-Goldstinofields.The general form of these terms,retaining operators through mass dimension6,is given byL(1)=1[DµλαQµMSSMα+¯QµMSSM˙αDµ¯λ˙α],(13)Fwhere QµMSSMαand¯QµMSSM˙αcontain the pure MSSMfield contributions to the conserved gauge invariant supersymmetry currents with once again all field derivatives being replaced by SUSY covariant derivatives and the vector field strengths in the standard realization.That is,it is this term in the effective Lagrangian which,using the Noether construction,produces the Goldstino independent piece of the conserved supersymmetry current.The Lagrangian L(1)describes processes involving the emission or absorption of a single helicity±1gravitino.Finally the remaining terms in the effective Lagrangian all contain two or more Goldstinofields.In particular,L(2)begins with the coupling of two8Goldstinofields to matter or gaugefields.Retaining terms through mass dimension8and focusing only on theλ−¯λterms,we can writeL(2)=1F2DµλαDν¯λ˙αMµν1α˙α+1F2Dµλα↔DρDν¯λ˙αMµνρ2α˙α+1F2DρDµλαDν¯λ˙αMµνρ3α˙α,(14)where the standard realization composite operators that contain matter and gaugefields are denoted by the M i.They can be enumerated by their oper-ator dimension,Lorentz structure andfield content.In the gauge mediated models,these terms are all generated by radiative corrections involving the standard model gauge coupling constants.Let us now focus on the pieces of L(2)which contribute to a local operator containing two gravitinofields and is bilinear in a Standard Model fermion (f,¯f).Those lowest dimension operators(which involve no derivatives on f or¯f)are all contained in the M1piece.After application of the Goldstino field equation(neglecting the gravitino mass)and making prodigious use of Fierz rearrangement identities,this set reduces to just1independent on-shell interaction term.In addition to this operator,there is also an operator bilinear in f and¯f and containing2gravitinos which arises from the product of det A with L(0).Combining the two independent on-shell interaction terms involving2gravitinos and2fermions,results in the effective actionIf¯f˜G˜G =d4x−12F2λ↔∂µσν¯λf↔∂νσµ¯f9+C ffF2(f∂µλ)¯f∂µ¯λ,(15)where C ff is a model dependent real coefficient.Note that the coefficient of thefirst operator isfixed by the normaliztion of the MSSM Lagrangian. This result is in accord with a recent analysis[10]where it was found that the fermion-Goldstino scattering amplitudes depend on only one parameter which corresponds to the coefficient C ff in our notation.In a similar manner,the lowest mass dimension operator contributing to the effective action describing the coupling of two on-shell gravitinos to a single photon arises from the M1and M3pieces of L(2)and has the formIγ˜G˜G =d4xCγF2∂µλσρ∂ν¯λ∂µFρν+h.c.,(16)with Cγa model dependent real coefficient and Fµνis the electromagnetic field strength.Note that the operator in the square bracket is odd under both parity(P)and charge conjugation(C).In fact any operator arising from a gauge and SUSY invariant structure which is bilinear in two on-shell gravitinos and contains only a single photon is necessarily odd in both P and C.Thus the generation of any such operator requires a violation of both P and ing the Goldstino equation of motion,the analogous term containing˜Fµνreduces to Eq.(16)with Cγ→−iCγ.Recently,there has appeared in the literature[11]the claim that there is a lower dimensional operator of the form˜M2F2∂νλσµ¯λFµνwhich contributes to the single photon-102gravitino interaction.Here˜M is a model dependent SUSY breaking massparameter which is roughly an order(s)of magnitude less than √.¿Fromour analysis,we do notfind such a term to be part of a SUSY invariant action piece and thus it should not be included in the effective action.Such a term is also absent if one employs the equivalent formalism of Wess and Samuel [6].We have also checked that such a term does not appear via radiative corrections by an explicit graphical calculation using the correct non-linearly realized SUSY invariant action.This is also contrary to the previous claim.There have been several recent attempts to extract a lower bound on the SUSY breaking scale using the supernova cooling rate[11,12,13].Unfortu-nately,some of these estimates[11,13]rely on the existence of the non-SUSY invariant dimension6operator referred to ing the correct low en-ergy effective lagrangian of gravitino interactions,the leading term coupling 2gravitinos to a single photon contains an additional supression factor ofroughly Cγs˜M .Taking√s 0.1GeV for the processes of interest and using˜M∼100GeV,this introduces an additional supression of at least10−12in the rate and obviates the previous estimates of a bound on F.Assuming that the mass scales of gauginos and the superpartners of light fermions are above the core temperature of supernova,the gravitino cooling of supernova occurs mainly via gravitino pair production.It is interesting to11compare the gravitino pair production cross section to that of the neutrino pair production,which is the main supernova cooling channel.We have seen that for low energy gravitino interactions with matter,the amplitudes for gravitino pair production is proportional to1/F2.A simple dimensional analysis then suggests the ratio of the cross sections is:σχχσνν∼s2F4G2F(17)where GF is the Fermi coupling and√s is the typical energy scale of theparticles in a supernova.Even with the most optimistic values for F,thegravitino production is too small to be relevant.For example,taking √F=100GeV,√s=.1GeV,the ratio is of O(10−11).It seems,therefore,thatsuch an astrophysical bound on the SUSY breaking scale is untenable in mod-els where the gravitino is the only superparticle below the scale of supernova core temperature.We thank T.K.Kuo for useful conversations.This work was supported in part by the U.S.Department of Energy under grant DE-FG02-91ER40681 (Task B).12References[1]D.V.Volkov and V.P.Akulov,Pis’ma Zh.Eksp.Teor.Fiz.16(1972)621[JETP Lett.16(1972)438].[2]P.Fayet and J.Iliopoulos,Phys.Lett.B51(1974)461.[3]R.Casalbuoni,S.De Curtis,D.Dominici,F.Feruglio and R.Gatto,Phys.Lett.B215(1988)313.[4]M.Dine and A.E.Nelson,Phys.Rev.D48(1993)1277;M.Dine,A.E.Nelson and Y.Shirman,Phys.Rev.D51(1995)1362;M.Dine,A.E.Nelson,Y.Nir and Y.Shirman,Phys.Rev.D53,2658(1996).[5]J.Ellis,K.Enqvist and D.V.Nanopoulos,Phys.Lett.B147(1984)99.[6]S.Samuel and J.Wess,Nucl.Phys.B221(1983)153.[7]J.Wess and J.Bagger,Supersymmetry and Supergravity,second edition,(Princeton University Press,Princeton,1992).[8]T.E.Clark and S.T.Love,Phys.Rev.D39(1989)2391.[9]T.E.Clark and S.T.Love,Phys.Rev.D54(1996)5723.[10]A.Brignole,F.Feruglio and F.Zwirner,hep-th/9709111.[11]M.A.Luty and E.Ponton,hep-ph/9706268.13[12]J.A.Grifols,R.N.Mohapatra and A.Riotto,Phys.Lett.B400,124(1997);J.A.Grifols,R.N.Mohapatra and A.Riotto,Phys.Lett.B401, 283(1997).[13]J.A.Grifols,E.Masso and R.Toldra,hep-ph/970753.D.S.Dicus,R.N.Mohapatra and V.L.Teplitz,hep-ph/9708369.14。

小学上册英语第1单元期中试卷英语试题一、综合题(本题有100小题，每小题1分，共100分.每小题不选、错误，均不给分)1.What is the capital of the United Arab Emirates?A. DubaiB. Abu DhabiC. SharjahD. AjmanB Abu Dhabi2.The ice cream is _______ (cold).3.What do you call a large body of saltwater?A. RiverB. OceanC. LakeD. PondB4.Which insect produces honey?A. AntB. BeeC. FlyD. MosquitoB5.How many hearts does an octopus have?A. OneB. TwoC. ThreeD. Four6.The ________ was a critical juncture in the history of gender equality.7.What is the name of the event where people come together to celebrate a birthday?A. PartyB. GatheringC. CelebrationD. EventA8.How many colors are there in a standard box of crayons?A. 8B. 16C. 24D. 48答案:C9.The _____ (花海) is a stunning sight in spring.10.She is _____ (playing) the flute.11. A _____ (蜗牛) moves very slowly.12.What do we call a young deer?A. FawnB. CalfC. KidD. Pup13.The ______ (小鸡) hatched from an egg yesterday.14.What is the opposite of "old"?A. AncientB. NewC. RecentD. Young15. A reaction that produces light is called a ______ reaction.16.I found a ________ under the couch.17.My sister is a great __________. (演讲者)18.He is playing in the ___. (sandbox)19.The Age of Exploration began in the ________ century.20.How many players are on a basketball team?A. FiveB. SixC. SevenD. Eight21.The __________ (盆地) is surrounded by mountains.22.What is the capital of Denmark?A. OsloB. StockholmC. CopenhagenD. HelsinkiC23.The ________ (team) is committed to success.24.The _____ of a star is determined by its size and temperature.25.What is the name of the superhero who wears a cape and flies?A. BatmanB. SupermanC. SpidermanD. IronmanB26.What do you call a person who plays music?A. ArtistB. MusicianC. PerformerD. DancerB27.My favorite sport is ________ (篮球). I practice every day with my ________ (朋友).28.What is the name of the imaginary line that divides the Earth into the Northern and Southern Hemispheres?A. EquatorB. Prime MeridianC. Tropic of CancerD. Tropic of CapricornA29.The country famous for its natural parks is ________ (美国).30.I love to visit the ________ (艺术馆) to see paintings.31.The chemical formula for potassium chloride is _______.32.My friend has a lot of __________ (梦想) for the future.33.The freezing point of water is _______ degrees Fahrenheit.34.When a solid is heated, it may ______.35.The first successful airplane flight was in _______.36.The zebra is known for its black and _________. (白条纹)37. A skunk sprays a strong ______ (气味) when threatened.38. A ______ is a type of energy related to heat.39.What do we call the art of making films?A. FilmmakingB. DirectingC. ProducingD. Cinematography40.What do we call a person who studies the effects of space on human behavior?A. Space PsychologistB. SociologistC. AnthropologistD. BiologistA41.Which vegetable is orange and long?A. PotatoB. CarrotC. TomatoD. CucumberB42.My ______ likes to cook delicious food.43. A _______ (兔子) can be a great pet.44. A solution that can conduct electricity is called an ______.45.What is the capital of Armenia?A. YerevanB. GyumriC. VanadzorD. VagharshapatA46.What is the name of the famous wizard in J.K. Rowling's books?A. DumbledoreB. Harry PotterC. VoldemortD. SnapeB47.I can ______ (表达) my feelings clearly.48.The ______ is crucial for survival in the wild.49.What is the name of the fairy tale character who had a magic lamp?A. AladdinB. CinderellaC. RapunzelD. Belle50.The __________ (公共交通) makes travel easier.51.My uncle is very _______ (形容词) about his job. 他总是 _______ (动词).52.Some plants are _______ and can be eaten.53.When it’s foggy, it’s hard to see ______ (远处).54.She has a ________ (passion) for helping others.55.My favorite game involves my toy ____. (玩具名称)56.He is _____ (playing/doing) video games.57.What is the fastest land animal?A. HorseB. CheetahC. LionD. AntelopeB58.The ________ was a significant battle in World War II.59.The _____ (pollen) is carried by the wind.60.In a chemical equation, the substances on the left side are called ______.61.What do you call a baby sheep?A. CalfB. KidC. LambD. Foal62.The angle of incidence equals the angle of ______ (reflection).63.The girl is very ________.64.I like to _____ (探索) different cuisines.65.The __________ is a large area of flat land in Europe.66.I have a _______ (collection) of stamps.67.My mom _____ breakfast every morning. (prepares)68.My mom enjoys gardening and planting ____ (vegetables).69.The chemical symbol for bismuth is ______.70.What is the main function of leaves on a plant?A. SupportB. PhotosynthesisC. ReproductionD. StorageB71.I enjoy watching ________ (比赛) at the stadium.72.What is the opposite of 'light'?A. HeavyB. DarkC. BrightD. Clear73.What is the freezing point of water in Celsius?A. 0B. 32C. 100D. -1A74.The __________ was a conflict between the North and South in 美国.75.Many people enjoy growing ______ in their gardens. (许多人喜欢在花园里种植蔬菜。