a r X i v :h e p -e x /0010049v 1 19 O c t 2000LAL 00-64
October 2000
Lower limit on the mass of the neutralino (LSP)at LEP with the ALEPH detector
Laurent Serin,on behalf of the ALEPH collaboration
Laboratoire de l’Acc′e l′e rateur Lin′e aire
IN2P3-CNRS et Universit′e de Paris-Sud,BP 34,F-91898Orsay Cedex,France
Abstract
The large amount of data accumulated at LEP2by the ALEPH experiment has been used to
search for supersymmetric particles.No signal has been found therefore limits have been deter-
mined.Within the Constrained Minimal Supersymmetric Standard Model,the constraints from direct SUSY searches of charginos,sleptons and neutralinos,are combined to extract a lower limit
on the mass of the neutralino considered to be the Lightest Supersymmetric particle.An improved limit is obtained when the limit on the Higgs mass is included.Neutralino masses up to 38GeV/c 2
are excluded at 95%con?dence level.
1Introduction In many supersymmetric models conserving R-parity,the neutralino as Lightest Supersymmetric Par-ticle,is considered to be a candidate for cold dark matter if its density does not over-close the Uni-verse [1].Experiments aiming at a direct detection of these Weakly Indirecting Massive Particles (WIMP)exist and are summarized in [2].On the other hand,at accelerator experiment,a lower limit on the mass of the neutralino can be also extracted and results from the combination of direct SUSY searches (charginos,sleptons,...).First the SUSY model used at LEP to obtain the excluded regions and the strategy to set a lower limit on the mass of the neutralino are discussed.Then the signal and background topologies are
explained.The exclusion and the limit on the neutralino mass are shown in section 3,including a discussion of the main sources of theoretical uncertainties.Finally,the impact of Higgs search is presented.
2De?nition of SUSY framework and strategy
Most of the results are interpreted at LEP in the Constrained Minimal Supersymmetric Standard Model (CMSSM)with R-parity conservation and with the assumption of GUT mass uni?cation.In this model a few parameters are enough to describe the properties of SUSY particles :
?m 0:the common sfermion mass at the GUT scale
?m 1/2:the common gaugino mass at the GUT scale
?A 0:the universal trilinear coupling
?tan β:the ratio of the two higgs doublet vacuum expectation values
?μ:the higgsino mass parameter
?m A:the CP-odd Higgs boson mass,relevant for the Higgs sector
The corresponding parameters at the electroweak scale are obtained by solving the Renormalization Group Equations.In practice M2is used as a free parameter instead of m1/2.From m0,M2and tanβthe slepton masses are derived,with the typical hierarchy:m?q?m??L～m?ν>m??R.As an example the slepton right mass can be written as:
=m02+0.22M22?sin2θW M2Z cos2β(1)
m2?
?R
The chargino and neutralino masses and couplings are fully speci?ed by M2,μ,tanβ.
If mixing in the scalar sector is not considered,the set of free parameters is reduced to:M2,μ, tanβ,m0.A scan over this4-parameter space is performed to search for the lowest allowed neutralino mass.Two regions,with distinct characteristics depending on the scalar mass m0,exist.For large scalar masses,chargino and neutralino limits are used.For low scalar masses,sleptons results must be included.Additional regions are excluded by Higgs constraints,especially for low tanβ.In order to be conservative,neutralino decays involving Higgs bosons are usually inhibited.
3Experimental context
Since1995,the LEP2e+e?collider has regularly increased its center of mass energy beyond the Z resonance.Table1shows the luminosity accumulated by ALEPH up to1999.The results presented in this paper use mainly the data accumulated at and above189GeV.
Table1:Luminosity accumulated by the ALEPH experiment
s L
The main characteristic of SUSY signals is the presence of neutralinos in the?nal state escaping detection,leading to acoplanar jets,acoplanar leptons or mixed jet/lepton topology.These events have a large missing mass and missing transverse momentum which depends strongly on the mass di?erence (?M)between the produced particle(chargino,slepton or heavy neutralino)and the neutralino(LSP), one of the decay products.Speci?c analyses have been designed depending on the mass di?erence and on the?nal state[3].
The cross section of the main Standard Model backgrounds is presented in Figure1:
?For small?M,theγγbackground is typically three orders of magnitude larger than expected signal,but cuts on missing mass or missing transverse momentum reduce this background to a very low level.
?For large?M,the QCD background can be easily rejected and the dominant background(WW, Weνand ZZ)is almost irreducible for some?nal states.
Figure1:Cross section of Standard Model backgrounds as function of the center of mass energy 4Excluded region and limit on the neutralino mass
4.1Sleptons
The sleptons are produced by pair in the s-channel viaγ,Z,and in the t-channel via neutralino exchange,leading to an increase of the cross section for selectron production.The?nal state consists of two leptons and two neutralinos(the e?ciency for cascade decays is assumed to be zero).No evidence of a signal was observed,e.g.in the1999data,42events were observed while39were expected from background[4].The main background comes from leptonic decays of WW events(the WW background is subtracted in all analyses involving at least one lepton).Figure2shows the limits obtained in the selectron-neutralino plane.Typically selectron masses up to95GeV/c2are excluded. As shown in equation1,at?xed tanβand for small scalar masses m0,this limit can be translated directly on a limit on M2.
4.2Charginos
Charginos are produced in the s-channel wiaγ,Z and in the t-channel with sneutrino exchange.This two diagrams interfere destructively for low scalar masses resulting in a reduction of the cross section. The decay proceeds via a three-body decay(W?)or a two-body decay(sneutrino-lepton for instance), leading to?nal states of4-jets,2-jets-lepton,and2-leptons.A map of the e?ciency and background expectation has been computed as a function of?M and the leptonic branching ratio.For heavy (light)sfermions,9(24)candidates are observed in1999data,while the expectation from background is12.7(33.9).The chargino exclusion for large scalar masses,shown in Figure2reaches the kinematic limit.For low scalar masses,when the chargino and sneutrino are almost mass-degenerate(a few GeV),the?nal state is practically invisible as the lepton energy,from the chargino decay,is too soft, leading to a non excluded corridor which is displayed on?gure3.
4.3Neutralinos
In contrast to charginos,the s-channel and the t-channel(via slepton exchange),show a constructive interference,thus an increase of the cross section for low scalar masses.All neutralino production
channels(χ01χ02,χ01χ03χ01χ04...)are taken into account.Final states considered are acoplanar jets and
e ～
μ (GeV/c 2)
Figure 2:ALEPH limit from selectron search in the selectron-neutralino mass plane.The yellow part is forbidden by theory.(left)and from neutralino and chargino searches for large scalar masses in the (M 2,μ)plane.The dark blue area shows the improvement of the limit with neutralino with respect to chargino exclusion alone (right).
M χ(G e V /c 2)Figure 3:Limit on the neutralino mass for m 0=500GeV/c 2versus tan β.The dashed line shows the limit obtained with charginos only (left).Illustration of the interplay among the various searches for low scalar masses with the 183GeV data :LEP1(1),chargino (2),neutralino (3),slepton (4)and Higgs (5)The corridor can be observed between the chargino exclusion in the higgsino and gaugino regions (right).
acoplanar leptons for low m0.For heavy(light)sfermions,5(78)candidates are observed,while3.1 (87.7)are expected from background.For large scalar masses,the neutralinos are useful in the higgsino region(|μ|>100)for low tanβand negativeμas shown in?gure2as they exclude region above the chargino kinematic limit.
4.4Limit on the neutralino mass
For large scalar masses the chargino and neutralino exclusions have been combined and Figure3shows the limit on the neutralino mass as a function of tanβ.The limit,given by neutralinos withχ04χ02 production for tanβ=1,is mχ>37GeV/c2at95%CL for m0>500GeV/c2.
To extract the absolute limit obtained for any m0,?rst the chargino and slepton searches are combined via parametrisations of e?ciency and maps of background.Then for each(m0,tanβ),for all the points not yet excluded with a neutralino mass<38GeV/c2,neutralino events are simulated, reconstructed and the analyses applied to determine if the point is excluded.The combined limit is: mχ>35GeV/c2at95%CL for any m0and tanβ
4.5Uncertainties on the LSP mass limit
A few caveats concerning the robustness of the LSP mass limit should be mentioned:
?The dependence of the limit on the mixing parameters,which induce an enhancement of chargino and neutralino decays to taus,must be studied.
?Radiative corrections to chargino and neutralino masses decrease the limit by about1GeV in the region where the limit is found.
?Higher order corrections to the one-loop GUT relation between M1and M2introduce a variation of a few%on the LSP mass limit.
The typical uncertainty on the LSP mass limit is therefore about2GeV.
5Higgs constraints on the neutralino mass limit
At tree level,the mass of the lightest supersymmetric Higgs,m h depends only on m A and tanβ,and is bounded by m Z|cos2β|.A limit on m h therefore gives directly a limit on tanβas soon as m A is?xed.As the radiative corrections to the Higgs mass introduce a dependence on the stop mass, i.e.the mixing parameter A t,the picture has to be re?ned.Fortunately large stop mixing,which means an increase of the Higgs mass,induces also a small stop https://www.doczj.com/doc/f512017540.html,ing the Higgs constraints for small mixing,and the stop search for large mixing,the exclusion obtained previously in the(M2,μ)plane can be substantially improved for low m0and tanβ.A scan over all possible values on m A and A t within the physical ranges is performed to obtain this limit.As an illustrative example,the improvement is shown in?gure3at183GeV.To update the results for a higher center of mass energy, the stops constraints are no longer useful and the(tanβ,m0,M2,μ)plane is scanned with the following procedure[5]:
?It has been shown that the dependence of the limit withμis negligible,the value has been?xed to?100GeV/c2where m h is maximal.
?m A has been?xed to2TeV/c2to maximize m h.A scan over A t is performed to determine the highest value of m h in each point,which is compared to the ALEPH Higgs mass limit on m h (107.7GeV/c2)(m t=175GeV/c2is used).
?The Higgs mass limit,if the radiative corrections are small,can be translated into a limit on tan β.In the other case,this limit can be translated into a limit on the stop mass,and therefore into a limit on M 2(assuming m 0is not too large).
Figure 4summarizes the exclusion obtained in the (M 2,tan β)plane from the Higgs limit.Any value of tan β<1.7is excluded.When increasing tan βup to about 3,a lower limit on M 2is obtained for small scalar masses (typically <200GeV/c 2).The result of the combination of the Higgs constraint with the previous limit on the neutralino mass is shown in Figure 4.Low tan βare excluded by Higgs constraints and supersedes the chargino/neutralino limit.However this limit is very sensitive,through the radiative corrections,to the top mass.If m t =180GeV/c 2,this exclusion do not hold,but a 40GeV/c 2neutralino mass is always excluded when tan β<3.If furthermore m 0is taken to be 2TeV/c 2,no more limit from Higgs can be used.Then the limit is given by the charginos exclusion at large scalar masses in a tiny region of tan β.Finally increasing with tan β,the neutralino limit is found in the corridor where charginos and neutralinos can not help.For tan β>3,only the slepton search contributes and the absolute limit is :
m χ>38GeV/c 2at 95%CL for any m 0and tan β
01002003004001234tan βM 2 (G e V /c 2)
35
40
45
50
55
110tan β
m χ (G e V /c 2)Figure 4:Higgs constraints in the (M 2,tan β)plane (left),and limit on the neutralino mass combining chargino,neutralino,slepton and Higgs contraints versus tan β(right)
6Conclusion
Using the large amount of data accumulated at LEP2by ALEPH ,the combination of direct searches of SUSY particles can be used to extract a lower limit on the mass of the neutralino,as as the Lightest Supersymmetric particle.A lower limit of 35GeV/c 2on the neutralino mass is obtained for any scalar mass m 0and tan β.Moreover,a limit of 38GeV/c 2is obtained including the Higgs contraints.At the end of LEP operation,a value of at least 40GeV/c 2should be reached if no signal is observed.
References
[1]J.Ellis,T.Falk,G.Ganis,K.A.Olive,CERN-TH/2000-106(2000)
[2]More details on the existing and future experiments in this domain can be found in these pro-
ceedings
[3]ALEPH coll.,Euro.Phys.J.C11(1999)193.
[4]ALEPH Coll.,ALEPH note for2000winter conference2000,ALEPH2000-012,CONF2000-009
[5]ALEPH coll.,ALEPH note for2000winter conference2000,ALEPH2000-019,CONF2000-016
J.B.De Vivie,Phd Thesis,Universit′e de Paris Sud Orsay,LAL-00-11,Apr2000
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高中英语~词性~句子成分~语法构成 第一章节：英语句子中的词性 1.名词：n. 名词是指事物的名称，在句子中主要作主语.宾语.表语.同位语。 2.形容词;adj. 形容词是指对名词进行修饰~限定~描述~的成份，主要作定语.表语.。形容词在汉语中是（的）.其标志是: ous. Al .ful .ive。. 3.动词：vt. 动词是指主语发出的一个动作，一般用来作谓语。 4.副词：adv. 副词是指表示动作发生的地点. 时间. 条件. 方式. 原因. 目的. 结果.伴随让步. 一般用来修饰动词. 形容词。副词在汉语中是（地）.其标志是：ly。 5.代词：pron. 代词是指用来代替名词的词，名词所能担任的作用，代词也同样.代词主要用来作主语. 宾语. 表语. 同位语。 6.介词：prep.介词是指表示动词和名次关系的词，例如：in on at of about with for to。其特征：
介词后的动词要用—ing形式。介词加代词时，代词要用宾格。例如：give up her（him）这种形式是正确的，而give up she（he）这种形式是错误的。 7.冠词：冠词是指修饰名词，表名词泛指或特指。冠词有a an the 。 8.叹词：叹词表示一种语气。例如：OH. Ya 等 9.连词：连词是指连接两个并列的成分，这两个并列的成分可以是两个词也可以是两个句子。例如：and but or so 。 10.数词：数词是指表示数量关系词，一般分为基数词和序数词 第二章节：英语句子成分 主语：动作的发出者，一般放在动词前或句首。由名词. 代词. 数词. 不定时. 动名词. 或从句充当。 谓语：指主语发出来的动作，只能由动词充当，一般紧跟在主语后面。 宾语：指动作的承受着，一般由代词. 名词. 数词. 不定时. 动名词. 或从句充当. 介词后面的成分也叫介词宾语。 定语：只对名词起限定修饰的成分，一般由形容
M A: Has the case been closed yet? B: No, the magistrate still needs to decide the outcome. magistrate n.地方行政官，地方法官，治安官 A: I am unable to read the small print in the book. B: It seems you need to magnify it. magnify vt.１．放大，扩大；２．夸大，夸张 A: That was a terrible storm. B: Indeed, but it is too early to determine the magnitude of the damage. magnitude n.１．重要性，重大；２．巨大，广大 A: A young fair maiden like you shouldn’t be single. B: That is because I am a young fair independent maiden. maiden n.少女，年轻姑娘，未婚女子 a.首次的，初次的 A: You look majestic sitting on that high chair. B: Yes, I am pretending to be the king! majestic a.雄伟的，壮丽的，庄严的，高贵的 A: Please cook me dinner now. B: Yes, your majesty, I’m at your service. majesty n.１．［Ｍ－］陛下（对帝王，王后的尊称）；２．雄伟，壮丽，庄严 A: Doctor, I traveled to Africa and I think I caught malaria. B: Did you take any medicine as a precaution? malaria n.疟疾 A: I hate you! B: Why are you so full of malice? malice n.恶意，怨恨 A: I’m afraid that the test results have come back and your lump is malignant. B: That means it’s serious, doesn’t it, doctor? malignant a.１．恶性的，致命的；２．恶意的，恶毒的 A: I’m going shopping in the mall this afternoon, want to join me? B: No, thanks, I have plans already. mall n.（由许多商店组成的）购物中心 A: That child looks very unhealthy. B: Yes, he does not have enough to eat. He is suffering from malnutrition.
意见应以事实为根据. 3 来自辞典例句 192. The bombers swooped ( down ) onthe air base. 轰炸机 突袭 空军基地. 来自辞典例句 193. He mounted their engines on a rubber base. 他把他们的发动机装在一个橡胶垫座上. 14 来自辞典例句 194. The column stands on a narrow base. 柱子竖立在狭窄的地基上. 14 来自辞典例句 195. When one stretched it, it looked like grey flakes on the carvas base. 你要是把它摊直, 看上去就象好一些灰色的粉片落在帆布底子上. 18 来自辞典例句 196. Economic growth and human well - being depend on the natural resource base that supports all living systems. 经济增长和人类的福利依赖于支持所有生命系统的自然资源. 12 1 来自辞典例句 197. The base was just a smudge onthe untouched hundred - mile coast of Manila Bay. 那基地只是马尼拉湾一百英里长安然无恙的海岸线上一个硝烟滚滚的污点. 6 来自辞典例句 198. You can't base an operation on the presumption that miracles are going to happen. 你不能把行动计划建筑在可能出现奇迹的假想基础上.
英语造句大全English sentence 在句子中，更好的记忆单词！ 1、(1)、able adj. 能 句子：We are able to live under the sea in the future. (2)、ability n. 能力 句子：Most school care for children of different abilities. (3)、enable v. 使。。。能句子：This pass enables me to travel half-price on trains. 2、(1)、accurate adj. 精确的句子：We must have the accurate calculation. (2)、accurately adv. 精确地 句子：His calculation is accurately. 3、(1)、act v. 扮演 句子：He act the interesting character. （2）、actor n. 演员 句子：He was a famous actor. (3)、actress n. 女演员 句子：She was a famous actress. (4)、active adj. 积极的 句子：He is an active boy. 4、add v. 加 句子：He adds a little sugar in the milk. 5、advantage n. 优势 句子：His advantage is fight. 6、age 年龄n. 句子：His age is 15. 7、amusing 娱人的adj. 句子：This story is amusing. 8、angry 生气的adj. 句子：He is angry. 9、America 美国n.
主语+谓语 1. 理解主谓结构 1) The students arrived. The students arrived at the park. 2) They are listening. They are listening to the music. 3) The disaster happened. 2．体会状语的位置 1) Tom always works hard. 2) Sometimes I go to the park at weekends.. 3) The girl cries very often. 4) We seldom come here. The disaster happened to the poor family. 3. 多个状语的排列次序 1) He works. 2) He works hard. 3) He always works hard. 4) He always works hard in the company. 5) He always works hard in the company recently. 6) He always works hard in the company recently because he wants to get promoted. 4. 写作常用不及物动词 1. ache My head aches. I’m aching all over. 2. agree agree with sb. about sth. agree to do sth. 3. apologize to sb. for sth. 4. appear (at the meeting, on the screen) 5. arrive at / in 6. belong to 7. chat with sb. about sth. 8. come (to …) 9. cry 10. dance 11. depend on /upon 12. die 13. fall 14. go to … 15. graduate from 16. … happen 17. laugh 18. listen to... 19. live 20. rise 21. sit 22. smile 23. swim 24. stay (at home / in a hotel) 25. work 26. wait for 汉译英： 1.昨天我去了电影院。 2.我能用英语跟外国人自由交谈。 3.晚上7点我们到达了机场。 4.暑假就要到了。 5.现在很多老人独自居住。 6.老师同意了。 7.刚才发生了一场车祸。 8.课上我们应该认真听讲。9. 我们的态度很重要。 10. 能否成功取决于你的态度。 11. 能取得多大进步取决于你付出多少努力。 12. 这个木桶能盛多少水取决于最短的一块板子的长度。
【it's time to和it's time for】 ——————这其实是一个句型,只不过后面要跟不同的东西. ——————It's time to跟的是不定式（to do）.也就是说,要跟一个动词,意思是“到做某事的时候了”.如： It's time to go home. It's time to tell him the truth. ——————It's time for 跟的是名词.也就是说,不能跟动词.如： It's time for lunch.(没必要说It's time to have lunch) It's time for class.(没必要说It's time to begin the class.) They can't wait to see you Please ask liming to study tonight. Please ask liming not to play computer games tonight. Don’t make/let me to smoke I can hear/see you dance at the stage You had better go to bed early. You had better not watch tv It’s better to go to bed early It’s best to run in the morning I am enjoy running with music. With 表伴随听音乐 I already finish studying You should keep working. You should keep on studying English Keep calm and carry on 保持冷静继续前行二战开始前英国皇家政府制造的海报名字 I have to go on studying I feel like I am flying I have to stop playing computer games and stop to go home now I forget/remember to finish my homework. I forget/remember cleaning the classroom We keep/percent/stop him from eating more chips I prefer orange to apple I prefer to walk rather than run I used to sing when I was young What’s wrong with you There have nothing to do with you I am so busy studying You are too young to na?ve I am so tired that I have to go to bed early
《The Kite Runner》追风筝的人--------------------------------美句摘抄 1.I can still see Hassan up on that tree, sunlight flickering through the leaves on his almost perfectly round face, a face like a Chinese doll chiseled from hardwood: his flat, broad nose and slanting, narrow eyes like bamboo leaves, eyes that looked, depending on the light, gold, green even sapphire 翻译：我依然能记得哈桑坐在树上的样子，阳光穿过叶子，照着他那浑圆的脸庞。他的脸很像木头刻成的中国娃娃，鼻子大而扁平，双眼眯斜如同竹叶，在不同光线下会显现出金色、绿色，甚至是宝石蓝。 E.g.: A shadow of disquiet flickering over his face. 2.Never told that the mirror, like shooting walnuts at the neighbor's dog, was always my idea. 翻译：从来不提镜子、用胡桃射狗其实都是我的鬼主意。E.g.:His secret died with him, for he never told anyone. 3.We would sit across from each other on a pair of high
一、翻译 1. The idea of consciously seeking out a special title was new to me., but not without appeal. 让我自己挑选自己最喜欢的书籍这个有意思的想法真的对我具有吸引力。 2.I was plunged into the aching tragedy of the Holocaust, the extraordinary clash of good, represented by the one decent man, and evil. 我陷入到大屠杀悲剧的痛苦之中，一个体面的人所代表的善与恶的猛烈冲击之中。 3.I was astonished by the the great power a novel could contain. I lacked the vocabulary to translate my feelings into words. 我被这部小说所包含的巨大能量感到震惊。我无法用语言来表达我的感情（心情）。 4，make sth. long to short长话短说 5.I learned that summer that reading was not the innocent(简单的) pastime(消遣) I have assumed it to be., not a breezy, instantly forgettable escape in the hammock(吊床)，( though I’ ve enjoyed many of those too ). I discovered that a book, if it arrives at the right moment, in the proper season, will change the course of all that follows. 那年夏天，我懂得了读书不是我认为的简单的娱乐消遣，也不只是躺在吊床上，一阵风吹过就忘记的消遣。我发现如果在适宜的时间、合适的季节读一本书的话，他将能改变一个人以后的人生道路。 二、词组造句 1. on purpose 特意，故意 This is especially true here, and it was ~. (这一点在这里尤其准确，并且他是故意的) 2.think up 虚构，编造，想出 She has thought up a good idea. 她想出了一个好的主意。 His story was thought up. 他的故事是编出来的。 3. in the meantime 与此同时 助记：in advance 事前in the meantime 与此同时in place 适当地... In the meantime, what can you do? 在这期间您能做什么呢？ In the meantime, we may not know how it works, but we know that it works. 在此期间，我们不知道它是如何工作的，但我们知道，它的确在发挥作用。 4.as though 好像，仿佛 It sounds as though you enjoyed Great wall. 这听起来好像你喜欢长城。 5. plunge into 使陷入 He plunged the room into darkness by switching off the light. 他把灯一关，房
The effective sentences:(improve the sentences!) 1.She hopes to spend this holiday either in Shanghai or in Suzhou. 2.Showing/to show sincerity and to keep/keeping promises are the basic requirements of a real friend. 3.I want to know the space of this house and when it was built. I want to know how big this house is and when it was built. I want to know the space of this house and the building time of the house. 4.In the past ten years,Mr.Smith has been a waiter,a tour guide,and taught English. In the past ten years,Mr.Smith has been a waiter,a tour guide,and an English teacher. 5.They are sweeping the floor wearing masks. They are sweeping the floor by wearing masks. wearing masks,They are sweeping the floor. 6.the drivers are told to drive carefully on the radio. the drivers are told on the radio to drive carefully 7.I almost spent two hours on this exercises. I spent almost two hours on this exercises. 8.Checking carefully,a serious mistake was found in the design. Checking carefully,I found a serious mistake in the design.
M1 U1 一. 把下列短语填入每个句子的空白处（注意所填短语的形式变化）： add up (to) be concerned about go through set down a series of on purpose in order to according to get along with fall in love (with) join in have got to hide away face to face 1 We’ve chatted online for some time but we have never met ___________. 2 It is nearly 11 o’clock yet he is not back. His mother ____________ him. 3 The Lius ___________ hard times before liberation. 4 ____________ get a good mark I worked very hard before the exam. 5 I think the window was broken ___________ by someone. 6 You should ___________ the language points on the blackboard. They are useful. 7 They met at Tom’s party and later on ____________ with each other. 8 You can find ____________ English reading materials in the school library. 9 I am easy to be with and _____________my classmates pretty well. 10 They __________ in a small village so that they might not be found. 11 Which of the following statements is not right ____________ the above passage? 12 It’s getting dark. I ___________ be off now. 13 More than 1,000 workers ___________ the general strike last week. 14 All her earnings _____________ about 3,000 yuan per month. 二.用以下短语造句： 1.go through 2. no longer/ not… any longer 3. on purpose 4. calm… down 5. happen to 6. set down 7. wonder if 三. 翻译： 1.曾经有段时间，我对学习丧失了兴趣。（there was a time when…） 2. 这是我第一次和她交流。（It is/was the first time that …注意时态） 3.他昨天公园里遇到的是他的一个老朋友。（强调句） 4. 他是在知道真相之后才意识到错怪女儿了。（强调句） M 1 U 2 一. 把下列短语填入每个句子的空白处（注意所填短语的形式变化）： play a …role (in) because of come up such as even if play a …part (in) 1 Dujiangyan(都江堰) is still ___________in irrigation(灌溉) today. 2 That question ___________ at yesterday’s meeting. 3 Karl Marx could speak a few foreign languages, _________Russian and English. 4 You must ask for leave first __________ you have something very important. 5 The media _________ major ________ in influencing people’s opinion s. 6 _________ years of hard work she looked like a woman in her fifties. 二.用以下短语造句： 1.make (good/full) use of 2. play a(n) important role in 3. even if 4. believe it or not 5. such as 6. because of
English sentence 1、(1)、able adj. 能 句子：We are able to live under the sea in the future. (2)、ability n. 能力 句子：Most school care for children of different abilities. (3)、enable v. 使。。。能 句子：This pass enables me to travel half-price on trains. 2、(1)、accurate adj. 精确的 句子：We must have the accurate calculation. (2)、accurately adv. 精确地 句子：His calculation is accurately. 3、(1)、act v. 扮演 句子：He act the interesting character.（2）、actor n. 演员 句子：He was a famous actor. (3)、actress n. 女演员 句子：She was a famous actress. (4)、active adj. 积极的 句子：He is an active boy. 4、add v. 加 句子：He adds a little sugar in the milk. 5、advantage n. 优势 句子：His advantage is fight. 6、age 年龄n. 句子：His age is 15. 7、amusing 娱人的adj. 句子：This story is amusing. 8、angry 生气的adj. 句子：He is angry. 9、America 美国n. 句子：He is in America. 10、appear 出现v. He appears in this place. 11. artist 艺术家n. He is an artist. 12. attract 吸引 He attracts the dog. 13. Australia 澳大利亚 He is in Australia. 14.base 基地 She is in the base now. 15.basket 篮子 His basket is nice. 16.beautiful 美丽的 She is very beautiful. 17.begin 开始 He begins writing. 18.black 黑色的 He is black. 19.bright 明亮的 His eyes are bright. 20.good 好的 He is good at basketball. 21.British 英国人 He is British. 22.building 建造物 The building is highest in this city 23.busy 忙的 He is busy now. 24.calculate 计算 He calculates this test well. 25.Canada 加拿大 He borns in Canada. 26.care 照顾 He cared she yesterday. 27.certain 无疑的 They are certain to succeed. 28.change 改变 He changes the system. 29.chemical 化学药品