考前综合检测(二)(时间：90分钟 分值：120分)

Unit 2 单元综合检测试题（时间90分钟，满分120分）学校：班级：姓名：学号：听力理解(本大题分为A、B、C、D四部分，共30小题，每小题1分，共30分)听单句话（本题有5小题，每小题1分，共5分）根据所听句子的内容和所提的问题，选择符合题意的图画回答问题，并将其字母编号写在题号前的括号内。

每小题听一遍。

（）1. What does my sister do at 7:30 every morning？（）2. What does Mr. Smith like doing in the morning？（）3. When does the speaker often have breakfast？（）4. What does Jenny do at eight every evening？（）5. What does the speaker's father do？B.听对话(本题有10小题，每小题1分,共10分)回答每段对话后面的问题,在每小题所给的三个选项中选出一个最佳答案,并将其字母编号写在题号前的括号内。

每段对话听两遍。

听第一段对话，回答第6小题。

（）6. What time does Mary brush her teethA.At 6:40 a.m.B. At 6:50 a.m.C. At 7:10 a.m.听第二段对话,回答第7小题。

（）7. What does Frank always do after schoolA. He always plays soccer.B. He always plays tennis.C. He alwaysplays basketball听第三段对话,回答第8小题。

（）8. What does the girl often drink for breakfastA. Orange juice.B. Milk.C. Tea.听第四段对话，回答第9小题。

第五～六章综合检测测试时间90分钟 分值120分班级________ 姓名________ 分数________第Ⅰ卷(选择题，共40分)一、选择题(本题共8小题，每小题5分，共40分．在每小题给出的四个选项中，有的小题只有一个选项正确，有的小题有多个选项正确．全部选对得5分，选不全的得2分，有选错或不答的得0分)1．静止在地球上的物体都要随地球的自转一起转动(如图)，下列说法正确的是( )A ．它们的运动周期都是相同的B ．它们的线速度都是相同的C ．它们的线速度大小都是相同的D ．它们的角速度都是相同的 答案：AD2．如图所示，两轮压紧，通过摩擦传动(无打滑)，已知大轮半径是小轮半径的2倍，E 为大轮半径的中点，C 、D 分别是大轮和小轮边缘上的一点，则E 、C 、D 三点向心加速度大小关系正确的是( )A ．a n C ＝a n D ＝2a n EB ．a nC ＝2a nD ＝2a nE C ．a n C ＝a n D /2＝2a n E D ．a n C ＝a n D /2＝a n E解析：同轴转动，C 、E 两点的角速度相等，由a n ＝ω2r ，有a n C /a n E ＝2，即a n C ＝2a n E ；两轮边缘点的线速度大小相等，由a n ＝v 2/r ，有a n C /a n D ＝1/2，即a n C ＝12a n D ，故选C.答案：C 3．汽车以某一恒定速率v 在水平公路上转弯时，受到的地面静摩擦力已经达到最大值，当汽车的速率增大为2v 时，要使汽车转弯时不打滑，则汽车转弯的半径必须( )A ．减为原来的1/2B ．减为原来的1/4C ．增大为原来的2倍D ．增大为原来的4倍 答案：D4．如图所示，用一本书托着黑板擦在竖直平面内做匀速圆周运动(平动)，先后经过A 、B 、C 、D 四点，A 、C 和B 、D 处于过圆心的水平线和竖直线上，设书受到的压力为F N ，对黑板擦的静摩擦力为F f ，则( )A．从C到D，F f减小，F N增大B．从D到A，F f增大，F N减小C．在A、C两个位置，F f最大，F N＝mgD．在B、D两个位置，F N有最大值解析：从黑板擦所受的重力、支持力、摩擦力的合力提供向心力，分别对各选项分析即可．答案：ABC5．若已知物体的速度方向和它所受恒定合外力的方向，则图中所示的运动轨迹可能正确的是()解析：如果知道物体的初速度方向和合外力方向，那么运动轨迹一定在这两个矢量之间，首先排除选项D.做曲线运动时，运动轨迹向合外力一侧偏转，选项A错误．在恒定的合外力作用下，物体的速度方向趋向于合外力方向，但不可能达到与合外力平行，选项B中有一个时刻的速度方向与合外力方向一致，是错误的．故选C.答案：C6．下列关于地球同步卫星的说法正确的是()A．它的周期与地球自转同步，但高度和速度可以选择，高度增大，速度减小B．它的周期、高度、速度都是一定的C．我们国家发射的同步通信卫星定点在北京上空D．我国发射的同步通信卫星也定点在赤道上空解析：同步卫星一定位于赤道上空，高度和速度都是一定的．答案：BD7．据媒体报道，嫦娥一号卫星环月工作轨道为圆轨道，轨道高度为200 km，运行周期为127分钟，若还知道引力常量和月球平均半径，仅利用以上条件不能．．求出的是()A．月球表面的重力加速度B．月球对卫星的吸引力C．卫星绕月球运行的速度D．卫星绕月运行的加速度解析：因为不知道卫星的质量，所以不能求出月球对卫星的吸引力．答案：B8．如图所示，小球A的质量为2m，小球B和C的质量均为m，B、C两球到结点P的线长相等，滑轮摩擦不计．当B、C两球以某角速度ω做圆周运动时，A球将()A．向上加速运动B．向下加速运动C．仍保持静止D．上、下振动解析：对B 进行受力分析：B 受到绳的拉力和重力作用．由于B 在水平面内做圆周运动，故绳的拉力在水平方向上的分力提供向心力，绳的拉力在竖直方向上的分力与重力平衡；C 球的受力分析同理．由此，两绳在P 点的竖直方向上的合力与B 、C 两球的重力相等，即F ＝2mg ，故A 球受力平衡，仍处于静止状态．答案：C第Ⅱ卷(非选择题，共80分)二、填空题(每题5分，共15分)9．在一次“飞车过黄河”的表演中，汽车飞经最高点后在对岸落地．已知汽车从最高点至落地点经历时间约0.8s ，两点间水平距离约为30m.若忽略空气阻力，g 取10m/s 2，则汽车在最高点时的速度约为____________m/s ，下落高度约为______m.解析：水平速度为：v 0＝x t ＝300.8m/s ＝37.5m/s ，下落的高度为：h ＝12gt 2＝12×10×0.82m＝3.2m.答案：37.5 3.2 10．在天文研究中，天文学家提出了一个大胆的假说——太阳伴星假说．这种理论认为，太阳不是形单影只的单身汉，它有一颗伴星，伴星有着巨大的质量，围绕太阳一周的时间是2600万年，它的巨大引力扰动着太阳系众多的小行星和彗星，造成它们越出自己的轨道，有时可能发生碰撞．已知太阳质量为 2.0×1030kg ，假设伴星的轨道是圆，不考虑其他星体的影响，则伴星与太阳之间的距离约为____________km.(保留一位有效数字)(已知G ＝6.7×10－11N·m 2/kg)解析：太阳的伴星绕太阳做圆周运动，其向心力是太阳对伴星的引力，由牛顿第二定律得G Mm r 2＝4π2mr T 2，r ＝3GMT 24π2，代入数据得r ＝1×1016m ≈1×1013km. 答案：1×101311．已知船在静水中的速度大小为4m/s ，河水的流速处处相同，且大小为2m/s ，测得该船经180s 到达河的正对岸，则河宽为__________m ，该船渡此河的最短时间为________s.解析：由于船到达河正对岸，合速度为v ＝ 42－22m/s ＝23m/s.由此得到河宽为d ＝v t ＝23m/s ×180s ＝3603m ，渡河的最短时间就是让船头垂直河岸，得到t min ＝d v ⊥＝36034s ＝903s.答案：3603 90 3三、实验题(共2小题，共12分)12．某同学设计了一个研究平抛运动的实验．实验装置示意图如下图所示，A 是一块平面木板，在其上等间隔地开凿出一组平行的插槽[图(a)中P 0P 0′、P 1P 1′……]，槽间距离均为d .把覆盖复写纸的白纸铺贴在硬板B 上．实验时依次将B 板插入A 板的各插槽中，每次让小球从斜轨的同一位置由静止释放．每打完一点后，把B 板插入后一槽中并同时向纸面内侧平移距离d .实验得到小球在白纸上打下的若干痕迹点，如图(b)所示．(1)实验前应对实验装置反复调节，直到________，每次让小球从同一位置由静止释放，是为了________．(2)每次将B 板向内侧平移距离d ，是为了________． (3)在图(乙)中绘出小球做平抛运动的轨迹． 解析：平抛运动可分解为水平方向的匀速直线运动和竖直方向的自由落体运动．实验前应对实验装置反复调节，直到斜槽末端水平，每次让小球从同一位置由静止释放，是为了保持小球水平抛出的初速度相同．每次将B 板向内侧平移距离d ，是为了保持相邻痕迹点的水平距离大小相同．有些考生不明白每次将B 板向内侧平移距离d 的道理．答案：(1)斜槽末端水平 小球每次平抛速度相同 (2)保持相邻痕迹点的水平距离大小相同 (3)如图所示13．图所示为某次实验所描绘的平抛物体运动轨迹，抛出点在O 点，A 、B 、C 三点的坐标为A (x 1＝0.369m ，y 1＝0.112m)，B (x 2＝0.630m ，y 2＝0.306m)，C (x 3＝0.721m ，y 2＝0.441m)，根据以上数据，分别用A 、B 、C 三点的数据计算物体平抛初速度，再求它们的平均值．答案：v A ＝2.44m/s v B ＝2.52m/s v C ＝2.40m/s v ＝2.45m/s四、论述计算题(本题共4小题，共53分，解答应写出必要的文字说明、方程式和重要演算步骤，只写出最后答案的不得分，有数值计算的题，答案中必须明确写出数值和单位)14．杂技演员表演飞车走壁时，至少要以多大速度才能在半径R ＝4m 的竖直筒体内表面某一高度处做匀速圆周运动？(设轮胎与筒体内表面的动摩擦因数为μ＝0.4，g 取10m/s 2)(最大静摩擦力等于滑动摩擦力)解析：杂技演员表演时，竖直方向为平衡态，水平方向为非平衡态，由正交分解法可以列出方程．演员受力情况：重力、筒体支持力、摩擦力(向上)，所以F N ＝m v 2R，F f ＝μF N ，F f＝mg .联立得：v ＝ Rgμ＝10m/s.答案：10m/s15．如图所示，车厢正在沿水平直轨道做匀速直线运动．车厢后部高h 的货架上有一小球P ，车厢忽然改以加速度a 做匀减速运动，则小球落到车厢底板上．小球落在底板上的点到货架的水平距离l 多大？解析：把车厢匀速运动的速度设为v 0，小球在空中飞行时间t ＝ 2hg，小球的水平位移l 1＝v 0t ，货架在t 时间内的位移l 2＝v 0t －12at 2，小球相对车厢的水平位移l ＝l 1－l 2＝12at 2＝12a ·2h g ＝ahg.答案：ah g16．“嫦娥一号”奔月成功这一事件极大地提高了同学们对月球的关注程度．以下是有关月球知识的几个问题，请解答：(已知月球质量为M ，半径为R ，引力常量为G )(1)若在月球上以初速度v 1竖直上抛一个物体，物体上升的最大高度h 1为多少？ (2)若在月球上发射一颗绕它运行的卫星，则该卫星的最大线速度v 2为多少？解析：(1)月球上物体的重力等于月球的引力，G MmR2＝mg解得：g ＝GMR2竖直上抛时物体做匀减速运动，得：h 1＝v 212g ＝v 21R22GM(2)贴着月球表面飞行时该卫星的线速度最大，G Mm R 2＝m v 22R解得：v 2＝ GMR .答案：(1)v 21R22GM (2) GM R17．如图所示，A 是地球的同步卫星．另一卫星B 的圆形轨道位于赤道平面内，距地面高度为h .已知地球半径为R ，地球自转角速度为ω0，地球表面的重力加速度为g ，O 为地球中心．(1)求卫星B 的运行周期．(2)如卫星B 绕行方向与地球自转方向相同，某时刻A 、B 两卫星相距最近(O 、B 、A 在同一直线上)，则至少经过多长时间，它们再一次相距最近？解析：(1)由万有引力定律和向心力公式得 G Mm (R ＋h )2＝m 4π2T 2B (R ＋h ) ①G MmR2＝mg ② 联立①②得T B ＝2π(R ＋h )3gR 2③(2)由题意得(ωB －ω0)t ＝2π ④由③得 ωB ＝gR 2(R ＋h )3⑤代入④得 t ＝2πgR 2(R ＋h )3－ω0答案：(1)2π (R ＋h )3gR 2(2)2πgR 2(R ＋h )3－ω0。

长沙市2021届中考考前仿真卷（二）英语（时间：120分钟分值：120分）班级___________ 姓名___________ 学号____________ 分数____________ I.知识运用（两部分，共10小题，计20分）第一节语法填空从题中所给的A、B、C三个选项中选择最佳答案填空．（共10小题，计10分）1．The dictionary is under the desk. Can you find _______？（）A．them B．her C．it D．one2．﹣﹣﹣I didn't see you at the party yesterday.﹣﹣﹣I for the final exam at that time.（）A．am preparing B．preparedC．was preparing D．prepare3．﹣Don't______your child run on the bus，It's dangerous.﹣Sorry，I won't.（）A．letting B．let C．let's4．﹣﹣﹣When was Tom born？﹣﹣﹣He was born December 10th，1996．（）A．on B．in C．at D．before5．He made a fire _______ himself _______ warm．（）A．make，to keep B．to make，to keepC．to make，keep D．make，keep6．I'll lend you my computer you promise to take good care of it.（）A．even though B．so thatC．as long as D．as soon as7．They were reading books when their father in.（）A．came B．comes C．has come D．will come8．Li Lei didn't go to bed his mother came back last night．（）A．after B．until C．because9．﹣Sir，you can't park on side of Zhongshan Road. Otherwise，you will be fined.﹣Sorry，I'm leaving. Thanks for telling me that.（）A．both B．either C．neither D．none10．﹣﹣﹣I don't care____ In this camp，there's only one hairstyle﹣short! Understand？（）﹣﹣﹣Yes，madam!A．what you are used to likingB．what you used to be likeC．what are you used to likingD．what did you use to be like第二节词语填空通读下面的短文，掌握其大意，然后从题中所给的A、B、C三个选项中选出最佳答案填空．（共1小题，计10分）Have you ever complained(抱怨) why life is so tiring? Does the sky sometimes seem dark to you? Are your lessons sometimes not successful? Well, friends, cheer up and 11 all the time. If you see the world with your warm heart, you’ll12 the whole world smiling to you.On a sunny morning, you plan to have a walk 13 yourself. Just before you go out, it suddenly starts to rain. Maybe you would feel very sad and start to complain about the 14 But dear friends, why 15 sit down and listen to the free concert that the nature brings you? And with the timely rain, crops in the fields will grow better and farmers will have a good harvest.Everyone wants to succeed in what he tries to do, 16 life isn’t a bed of roses. It’s very common to meet difficulties on the way 17 success. In fact, difficulty isn’t terrible. The real terrible thing is that we are afraid of it. Difficulty is like spring（弹簧）. If you are 18 , it will be strong. Attitude（态度）decides 19 . With an optimistic (乐观的) attitude, life is easy and pleasant. So when you meet difficulties, don’t give up. Instead, you should face them with a smile. Remember these five rules: Free your heart from hate; Free your mind from worries; Live an easy life; Give more; Expect 2011．A．happy B．unhappy C．smile D．cry12．A．look B．look for C．find D．find out 13．A．enjoying B．to relax C．relax D．enjoy14．A．time B．whether C．weather D．place 15．A．don’t B．didn’t C．haven’t D．not16．A．but B．and C．or D．so17．A．of B．to C．about D．for 18．A．energetic B．powerful C．confident D．weak 19．A．anything B．something C．everything D．nothing 20．A．little B．few C．less D．FewerII.阅读技能（四部分，共2小题，计48分）第一节图表理解阅读下列图表，从每题所给的A、B、C三个选项中，选出最佳选项回答问题或完成句子．（共2小题，计10分）AWelcome to our school clubsEnglishTime：Monday & Wednesday 5：00 ﹣6：00 in the afternoon Place ：English cornerTeacher：DennisTel：1895 ﹣3421SwimmingTime：Friday4：30 ﹣5：30 in the afternoon Place ：swimming poolTeacher：Mr．ZhangTel：6213 ﹣6726ArtTime ：Monday & Friday 5：00 ﹣6：00 in the afternoon Place ：art roomTeacher：Miss LiTel：2816 ﹣3218DancingTime ：Tuesday & Thursday 4：30 ﹣5：30 in the afternoon Place ：dancing roomTeacher：Miss PanTel：3517 ﹣3587（21）The place for kids to learn English is．A．English corner B．swimming pool C．art room D．dancing room （22）Kids can go to school clubs to learn on Friday．A．English and swimmingB．English and artC．swimming and artD．art and dancingBAfter a long flight of about 380,000 kilometers and 26 days, on January 3rd Chang' e No.4 landed on the back of the moon, making it the first try in human history. How do people observe （观察）the space in the kilometers and long history? Thanks to the astronomer, Galileo, who built a strong telescope（望远镜）enough about 400 years ago, we can understand study the sky well.See with our eyesOn a dark and clear night, we can see stars shine brightly（明亮地）. In fact, the Sun is also a star. The reason why it seems bigger than other stars is that it is the closest to the Earth. The brightest planet we can see at night is the Moon, but what you can see is just a bright ball. Unless you have a good eyesight, you can find some dark parts on the Moon.See with a simple telescopeIf you watch the sky with a simple telescope, like the one Galileo used, you can find that the Moon is full of mountains and holes. The bright parts are the mountains, while the dark parts are the holes, or craters. However, we can never see the back side of it, because the Moon always keeps its front side to the Earth. This time, Chang' e No.4 is going to find out the unknown secrets on its back side.See with the Hubble TelescopeBuilt by the United States space agency（NASA）, Hubble is one of the largest and strongest telescopes used as a tool to study the universe（宇宙）.With its help, watching the Moon or the Sun is just a piece of cake. We can even use it to do something more difficult, for example, we can not only see the planets outside our solar system（太阳系）clearly, but also find bigger stars than the Sun many light years away!23．Why does the writer use the example of Chang'e No.4 in Para 1?A．To tell the main idea of this passage.B．To catch our interest to read the passage.C．To tell us that China is becoming stronger.D．To echo（呼应）the ending of the passage.24．What can we see with our eyes?A．The front side of the Moon. B．The back side of the Moon.C．The craters on the Moon. D．Chang'e No.4.25．What CANNOT we do with the help of the Hubble Telescope?A．Watch the Sun clearly B．Find stars outside the universe.C．See planets outside the solar system. D．Observe stars inside the solar system.第二节短文理解阅读下面的短文，从题中所给的A、B、C三个选项中，选出最佳选项回答问题或完成句子．（共2小题，计20分）There’s much to see under the sea, but you need to remember that light behaves differently in water than in air. The objects appear closer to you than they exactly are. You might find yourself reaching out to touch something and completely missing it.Objects under water will appear larger than they would on the surface, too. Be careful not to tell any stories about the big fish that got away. The fish might not be so big after all! It’s just because sometimes things can seem to be as much as about 33 percent bigger in water!What’s more, in deeper water, colors just don’t seem as bright. In fact, it looks as if some colors are missing. Remember the color of an object results from the wavelengths(波长) of light that are reflected from its surface. And light is taken in as it moves down through the water.Swimmers wear wet suits to keep warm underwater. Let’s take a bright red, yellow, and blue wet suit as an example. These colors are hard to miss on the surface of water. Watch carefully the changes in color as you descend in water. The red part now looks almost black because the red light wavelengths, the longest among these three colors, are missing. As you go down deeper, the same thing will happen to the yellow part and in the end to the blue part. Even at a place of about 6 to 9 meters underwater, you will look terrible, like a ghost(鬼怪)! And you have to wait for your return to the surface to enjoy the bright colors again.Do you have a better understanding of the behavior of the light underwater? We need to be careful about the objects around us and explore(探索) their mysteries by ourselves.26．You miss the object underwater when you want to touch it because___________. A．your eyesight is quite poorB．your are not quick enoughC．it is not as close as it seemsD．it disappears very quickly27．The example of the wet suit is used to explain the change of __of an object underwater in paragraph 4.A．the size B．the color C．the position D．the weight 28．The underlined word “descend” probably means _________ in paragraph 4?A．move up B．move on waterC．stop breathing for a while D．go down29．Which of the following is true according to the passage?A．A four-meter-long fish looks three meters long underwater.B．Much water will be taken in by the swimmer deep in the water.C．The wavelengths of red light are longer than those of the blue light.D．You will see a ghost if you go as deep as 6 to 9 meters into the sea.30．Which of the following would be the best title of the passage?A．The Standard of Color UnderwaterB．The Direction of Light UnderwaterC．The Beauty of Color UnderwaterD．The Behavior of Light UnderwaterDecisions，decisions! Our lives are full of them，from the small ones to the life changing. The right choice is central to everyone. Yet sometimes we make bad decisions that leave us unhappy or full of regret. Can science help？Most of us know little about the mental processes that lie behind our decisions. Luckily，what psychologists （心理学家）are finding may help us all make better choices. Here are some of their amazing discoveries to help you make up your mind.Consider your emotions. You might think that emotions are the enemy of decision making，but in fact they are a part of it. Whenever you make up your mind，your brain's emotional centre is active. University of Southern California scientist，Antonio Damasia，has studied people with damage to only the emotional parts of their brains，and found that they were unable to make basic choices about what to wear or eat. Damasia thinks this may be because our brains store emotional memories of past choice，which we use to help the present decision﹣making.However，making choices under the influence of an emotion can greatly affect the result.Take anger，for example. A study by Nitika Garg of the University of Mississippi and other scientists found the angry shoppers were more likely to choose the first thing they were offered rather than considering other choices. It seems that anger can lead us to make quick decisions without much thinking.All emotions affect our thinking and motivation（动机），so it may be best to avoid making important decisions under their influence. Yet strangely there is one emotion that seems to help us make good choices. The American researchers found that sad people took time to consider the various choices on offer，and ended up making the best choices. In fact many studies show that people who feel unhappy have the most reasonable view of the world.（31）What does the underlined word "central" mean？A. 中心的B. 中央的C. 重要的D. 后悔的（32）According to the text，what may help us make btter dcisions？A. To think about happy times.B. To make many decisions at a time.C. To stop feeling regretful about the past.D. To learn about the process of decision making.（33）Damasia's study suggests that.A. emotions are the enemy of decision making.B. our brain has nothing to do with decision making.C. people with physical damage find it hard to make up their minds.D. our emotional memories of past choices can affect present decisions.（34）Why are angry shoppers more likely to choose the first thing they are offered？A. They often forget their past choices.B. They make decisions without much thinking.C. They tend to save time when shopping.D. They are too angry to bargain.（35）What do we learn from the text？A. Emotions are a part of decision﹣making.B. Sad people always make worse choices.C. No emotion seems to help us make good choices.D. Only sad feeling affect our thinking and motivation.第三节语篇补全阅读下面的短文，从短文后的选项中选出能填入空白处的最佳选项补全短文．选项中有一项为多余选项．（共1小题，计8分）Studying makes you tired？How to deal with the worries and relax yourself？Here is some advice which may add happiness to your life．（36）Weekends are time for a rest．After a week's hard work，weekends are the best time for you to relax yourself．Having a nice lie﹣in （睡懒觉）is a good idea．Besides，good sleep makes sure of your study．（37）If you feel sad，don't try to hide your feelings．Crying out may help reduce（减少）your sadness．（38）You may have heard about "Blog"．It means writing online diaries．It's a very great way to think about and remember life．（39）It's not a good idea for a kid to lose weight，so you don't need to eat less food．When you feel upset，enjoy a big meal．Eating delicious food will make you feel good．Take part in more activities．Having a get﹣together is great fun．Going out with friends for a picnic or swimming or running will make you happy．And it will also bring you a good sleep．根据短文内容选择合适的标题．A．Chat（聊天）online．B．Blog your life．C．Enjoy a big meal．D．Rest on weekends．E．Express（表达）your feelings．第四节阅读表达阅读下面的短文，然后根据短文内容回答问题．（共1小题，计10分）Do you often go shopping？What do you often buy and how much money do you oftenspend（花费）？It's important for you to be a clever shopper．Next time，when you go to a clothes shop，you should first decide（决定）how much money you can spend on the new clothes．You must think about the clothes you really need．Then look for them in the shop．Don't buy anything that you don't need．Many clothes must be dry cleaned（干洗）．Dry cleaning is very expensive．So before you buy new clothes，you should look at the labels（标签）inside carefully．You must find out（弄明白）if（是否）they need dry cleaning．If you don't want to spend too much money，don't buy those clothes．Some clothes cost much money，but they are not always good．Some clothes look nice only on models（模特）．Some cheap clothes may fit you better．So expensive things are not always the best．（40）回答问题．Why shouldn't we buy the clothes that need dry cleaning？（41）在空白处填上适当的单词，每空一词．We should look at the labels carefully before new clothes．（42）将画线的句子翻译成汉语．（43）从文中找出与下面句子意思相近的句子．Some clothes are very expensive，but sometimes they are not so good．（44）找出最能表达该短文主题的句子．五.写作技能（三部分，共1小题，计32分）第一节语篇翻译阅读下面的短文，将划线部分译成英文或中文．（共1小题，计10分）Henry was a kind，good boy. His father was dead，and his mother was very poor. He had a little sister about 2 years old. He wanted to help his mother（1）she could not always earn （挣）enough money to buy food for his little family.One day a man gave him a dollar for returning the pocketbook which he had lost. Henry could have kept the pocketbook because no one saw him when he found it. But his mother had taught him to be honest，and never to keep what did not belong to him. So he gave the pocketbook back to the man.With the dollar he bought a box，three brushes and some shoe polish （鞋油）. He thenwent to the corner of the street，and said to everyone whose boots did not look nice . "Polish your boots，please？"He was so polite that gentlemen soon began to notice him，and to let him polish their boots. The first day he made over 50 cents. （A）He couldn't wait to run home and give the money to his mothe. He hoped that his mother to buy food with it.（B）当他把钱给她时，她禁不住高兴地喊叫起来。

章末综合检测（时间：90分钟分值：120分）一、选择题（每小题3分，共30分）1.用－a表示的数一定是（）A.负数B.负整数C.正数或负数或0D.以上结论都不对2.如果＋10%表示“增加10%”，那么“减少8%”可以记作（）A．－18% B．－8%C．＋2% D．＋8%3.下面的说法正确的有（）①一个有理数不是整数就是分数；② 0既不是整数也不是分数；③一个有理数不是正数就是负数；④一个分数不是正的就是负的.A.1个B.2个C.3个D.4个4.地球上的海洋面积约为361 000 000平方千米，数字361 000 000用科学记数法表示为（）A．36.1×107B．0.36×109C．3.61×108D．3.61×1075.用科学计算器求35的值，按键顺序是（）6.-|-32|的相反数是（）7.A 为数轴上表示-2的点，当点A 沿数轴移动4个单位长度到达点B 时，点B 所表示的数为 （ ）A ．2B ．-6C ．2或-6D ．以上答案都不对8.绝对值不大于8的所有整数的和，绝对值小于6的所有负整数的积分别是 （ ）A.0 0B.10 0C.0 -120D.5 1209.如果（a +1）2+（2b +3）2+|c －1|=0，那么 3ab c +a c b的值是 （ ） A.32 B.3 C . 76 D. 11610.某种品牌的同一种洗衣粉有A ，B ，C 三种袋装包装，每袋分别装有400克、300克、200克的洗衣粉，售价分别为3.5元、2.8元、1.9元.A ，B ，C 三种包装的洗衣粉，每袋的包装费用（含包装袋成本）分别为0.8元、0.6元、0.5元.厂家销售A ，B ，C 三种包装的洗衣粉各1 200千克，获得利润最大的是 （ ）A.A 种包装的洗衣粉B.B 种包装的洗衣粉C.C 种包装的洗衣粉D.三种包装的都相同二、填空题（每小题4分，共32分）11.－31的相反数是____，－31的绝对值是____，－31的倒数是___.12.某食品包装袋上标有“净含量385克±5克”，这包食品的合格净含量范围是_____克～____克．13.在（-1）2 017，（-1）2 018，-22，（-3）2中，最大的数与最小的数的和等于______．14.a 是最小的正整数，b 是最小的非负数，m 表示大于-4且小于3的整数的个数，则a -b +m =_____.15.已知a ，b 互为相反数，且|a -b |=6，则b -1=_____.16.观察下列算式:21=2，22=4，23=8，24=16，25=32，26=64，27=128，28=256，….通过观察，根据所发现的规律可确定215个位上的数字是______.17.定义运算“@”的运算法则为x @y =xy -1，则（2@3）@4=______.18.已知：23C =212×3⨯=3，35C =321345⨯⨯⨯⨯=10，46C =4×3×21?3×4×5×6=15，…，观察上面的计算过程，寻找规律并计算610C =_______．三、解答题（共58分）19.（8分）把下列各数填入相应的集合内：+8.5，-321，0.3，0，-3.4，12，-9，431，-1.2，-2.（1）正数集合:｛___________…｝；（2）整数集合:｛___________…｝；（3）非正整数集合:｛_____________…｝；（4）负分数集合:｛ ________________…｝.20.（8分）计算下列各题：（1）3.587-（-5）+（-521）+（+7）-（+341）-（+1.587）；（2）（－1）5×{[－432÷（－2）2+（－1.25）×（－0.4）]÷（－91）－32}.21.（10分）阅读：比较1110与109的大小. 方法一：利用两数差的正负来判断. 因为1110－109=1101＞0，所以1110＞109. 方法二：利用两数商，看商是大于1还是小于1来判断.因为1110÷109=99100＞1，所以1110＞109. 请用以上两种方法，比较－54和－65的大小. 22.（10分）若a 与2互为相反数，c 与d 互为倒数，m 的平方与它本身相等，请你求3m -2a cd+2cd 的值. 23.（10分）为了节约用水，某城市用水标准为：居民每户用水未超过7立方米时，每立方米收水费1.00元，并加收每立方米0.2元的城市污水处理费；超过7立方米的部分每立方米收水费1.50元，并加收每立方米0.4元的城市污水处理费.李明家1月份用水10立方米，2月份用水6立方米，请你计算他家这两个月共缴水费多少元？（2）（-1）2+22_______2×（-1）×2;（3）（-3）2+312______2×（-3）×31; （4）32+32_______2×3×3;答案一、1．C 解析：当a 表示正数时，-a 表示负数；当a 表示负数时，-a 表示正数；当a 表示0时，-a 表示0.故选C.2．B3．B4．C 解析：361 000 000=3.61×108.故选C.5．A6．A 解析：-|-32|=-32，它的相反数为32.故选A.7．C 解析：点A 在数轴上移动的方向有两种情况：向左（负方向）或向右（正方向）．当点A 沿数轴向左移动4个单位长度到达点B 时，点B 所表示的数为-2-4=-6；当点A 沿数轴向右移动4个单位长度到达点B 时，点B 所表示的数为-2+4=2．综上可知，点B 所表示的数为2或-6．故选C ．8.C 解析：绝对值不大于8的所有整数有1，2，3，4，5，6，7，8，0，-1，-2，-3，-4，-5，-6，-7，-8，它们的和等于0.绝对值小于6的所有负整数有-1，-2，-3，-4，-5，其积为-120.故选C.9.D 解析：因为（a +1）2+（2b +3）2+|c -1|=0，所以a =-1，b =-23，c =1.所以3ab c +a c b -=1323-×(-1)⨯）（+23-1-1-=21+34=611.故选D. 10.B 解析：因为利润=售价-成本，所以A 种包装的洗衣粉每袋的利润为3.5-0.8=2.7（元），B 种包装的洗衣粉每袋的利润为2.8-0.6=2.2（元），C 种包装的洗衣粉每袋的利润为1.9-0.5=1.4（元）.因为销售这三种包装的洗衣粉各1 200千克，所以A 种包装的洗衣粉获得的利润为2.7×400000 200 1=8 100 （元），B 种包装的洗衣粉获得的利润为2.2×300000 200 1=8 800 （元），C 种包装的洗衣粉获得的利润为1.4×200000 200 1=8 400（元）.所以获得利润最大的是B 种包装的洗衣粉.故选B.二、11. 13 13 -312. 380 39013. 5 解析：（-1）2 017=-1，（-1）2 018=1，-22=-4，（-3）2=9，其中最大的数是9，最小的数是-4，它们的和等于5.14. 7 解析：根据题意，得a =1，b =0，m =6，则a -b +m =1-0+6=7.15. 2或-4 解析：由a ，b 互为相反数，可得a +b =0，所以a =-b .由|a -b |=6，得|-b -b |=6，|b |=3，所以b =3或b =-3.当b =3时，b -1=2;当b =-3时，b -1=-4.16. 8 解析：观察规律可得，2n 个位上的数字每4个一循环，因为15÷4=3……3，所以215个位上的数字是8.17. 19 解析：根据运算法则x @y =xy -1，知（2@3）@4=（2×3-1）×4-1=19.18. 210 解析：观察运算式子会发现分子、分母中因数的个数相同且等于等式左边符号中的上标，分子中最大的因数是左边符号中的下标，且每个因数逐次减1；分母中最小的因数是1，且每个因数逐次加1，所以610C =1098765123456⨯⨯⨯⨯⨯⨯⨯⨯⨯⨯=210． 三、19.解：（1）正数集合: {+8.5，0.3，12，431，…}.（2）整数集合:｛ 0，12，-9，-2，…｝.（3）非正整数集合:｛ 0，-9，-2，…｝.（4）负分数集合:{-321，-3.4，-1.2，…}.20.解：（1）原式=3.587+5-521+7-341-1.587=（3.587-1.587）+（5+7）+（-521-341）=541.（2）原式＝-1×{[-314÷4+0.5]÷（-91）-9} ＝-1×[（-32）÷（-91）-9] ＝-1×（6-9）＝-1×（-3）＝3.21.解：方法一：因为54-65=-301<0，所以54<65，从而-54>-65. 方法二：因为54÷65=2524<1，所以54<65，从而-54>-65. 22.解：因为a 与2互为相反数，所以a +2=0.因为c 与d 互为倒数，所以cd =1.因为m 的平方与它本身相等，所以m =0或m =1.当m =0时，3m -2a cd++2cd =0-0+2=2； 当m =1时，3m -2a cd++2cd =13-0+2=37. 综上可知，3m -2a cd++2cd 的值为2或37. 23.解：李明家1月份应缴水费：7×（1.00+0.2）+（10-7）×（1.50+0.4）=7×1.2+3×1.9=14.1（元）. 2月份应缴水费：6×（1.00+0.2）=6×1.2=7.2（元）.所以小明家这两个月共缴水费14.1+7.2=21.3（元）.24.解：（1）>.（2）>.（3）>.（4）=.（5）结论：对于任意有理数a，b，都有a2+b2≥2ab，当a≠b时，a2+b2>2ab；当a=b时，a2+b2=2ab.。