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    精英家教网如图1是小莉、小华和小明三人在做“探究凸透镜成像规律”的实验装置图：
    （1）小明将凸透镜正对太阳光，在透镜的另一侧移动光屏，直至屏上呈现出
     
    的光斑，量出透镜到光斑的距离为10cm．则此凸透镜的焦距约是
     
    cm．
    （2）小华在凸透镜成像实验中，把蜡烛放在该凸透镜的焦点上，凸透镜固定不动，将光屏向远离凸透镜的方向移动的过程中，在光屏上观察到的现象是大小
     
    的光斑，把蜡烛放在该凸透镜的焦点内，凸透镜固定不动，将光屏向远离凸透镜的方向移动的过程中，在光屏上观察到的现象是大小
     
    的光斑（填“不变”、“变大”、“变小”）．
    （3）小莉同学做实验时，小华发现烛焰在光屏上的像如图1所示，若要使烛焰在光屏中心成像，只调节透镜，小莉应将透镜向
     
    （选填“上”或“下”）移动．改正后若实验时固定蜡烛与透镜，无论怎样移动光屏，屏上都不出现清晰像，原因可能是
     
    ．当蜡烛距离凸透镜10.3cm时，无论怎么样移动光屏都得不到像，原因是
     
    ．
    精英家教网
    （4）小明将烛焰移至距凸透镜 15cm 处，移动光屏，使烛焰在屏上得到清晰的倒立、
     
    实像，
     
    （选填“照相机”、“投影仪”或“放大镜）就是应用这一原理制成的．
    （5）小莉同学将自己的近视眼镜镜片放在了蜡烛与凸透镜（靠近凸透镜）之间，小明移动透镜和光屏，直到在光屏上得到了一个倒立缩小的清晰的像．将近视眼镜镜片取下，发现光屏上的像变模糊了．
    ①为了使屏上的像重新变得清晰，在不移动蜡烛和凸透镜位置的前提下，小华应将光屏向
     
    （左/右）移动．
    ②下列四个选项中，正确表示小莉同学近视眼成像和近视眼矫正情况的是图2中的
     
    ．
    A．乙  甲    B．丙  甲     C．乙  丁     D．丙  丁
    （6）当烛焰通过凸透镜在光屏上成一实像时，如果小明用书遮挡住透镜下半部分，则实验时光屏上所成的像
     
    （选填“完整”或“不完整”），像的明暗程度将
     
    （选填“变亮”或“变暗”或“不变”）．
    （7）蜡烛通过凸透镜恰好在光屏上得到放大的清晰的像，若保持凸透镜的位置不变把蜡烛和光屏的位置对调，则光屏上
     

    A．不能成像     B．可以成像，但要适当移动位置  C．可以成像，像大小不变 D．可以成像，像变小
    （8）蜡烛通过凸透镜恰好在光屏上得到放大的清晰的像，若拿下光屏，移动眼睛的位置
     
    （“能”或“不能”）看到像．
    （9）一物距应只有唯一的像距，他们三人将蜡烛都放在透镜前15厘米处时，但他们所测得的像距却并不相同，分别为28cm，30cm，31cm，他们的数据不是因为测量长度误差造成的，你认为出现这种现象的原因是
     
    ．精英家教网
    （10）小华又将两支点燃的蜡烛、凸透镜和光屏分别置于如图3所示的位置时，光屏上C、D两处会得到清晰的烛焰像．这像是
     
     （选填“缩小”、“等大”或“放大”）的烛焰的像．用一厚纸板挡住A处的烛焰，在光屏上
     
     （选填“C”或“D”）处仍能得到一个清晰的烛焰像．

    查看答案和解析>>

    There was a boy who was sent by his parents to a boarding school (寄宿学校).   36   being sent away, this boy was the   37   student in his class. He was at the top in every   38   always with high marks.
    But the boy changed after   39   home and attending the boarding school. His grades started   40  . He hated being in a   41  . He was lonely all the time. And there were especially dark times when he   42   committing suicide (自杀). All of this was because he felt   43   and no one loved him.
    His parents started   44   about the boy. But they even did not know what was   45   with him. So his dad decided to travel to the boarding school and   46   him.
    They sat on the bank of the lake near the school. The father started asking him some casual questions about his classes, teachers and   47  . After some time his dad said, “Do you know, son, why I am here today?”
    The boy answered back, “To   48   my grades?”
    “No, no,” his dad replied. “I am here to tell you that you are the most   49   person for me. I want to see you   50  . I don’t care about grades. I care about you. I care about your happiness. YOU ARE MY LIFE.”
    These words   51   the boy’s eyes to be filled with tears. He   52   his dad. They didn’t say anything to each other for a long time.
    Now the boy had   53   he wanted. He knew there was someone on this earth who cared for him deeply. He   54   the world to someone. And today this young man is in college at the top of his class and no one has ever seen him   55  !
    【小题1】
    A．AfterB．BeforeC．WhenD．While
    【小题2】
    A．hardestB．naughtiestC．brightestD．dullest
    【小题3】
    A．examB．activityC．gameD．class
    【小题4】
    A．comingB．returningC．leavingD．reaching
    【小题5】
    A．risingB．increasingC．reducingD．dropping
    【小题6】
    A．groupB．termC．company D．party
    【小题7】
    A．led toB．felt likeC．thought backD．looked for
    【小题8】
    A．worthless B．carelessC．concernedD．annoyed
    【小题9】
    A．caringB．turningC．worryingD．speaking
    【小题10】
    A．crazyB．trueC．possibleD．wrong
    【小题11】
    A．talk withB．listen toC．tell toD．care about
    【小题12】
    A．familyB．friendsC．studyD．grades
    【小题13】
    A．realizeB．analyzeC．checkD．test
    【小题14】
    A．outstandingB．importantC．famousD．familiar
    【小题15】
    A．happyB．excellentC．interestedD．satisfied
    【小题16】
    A．causedB．wantedC．encouragedD．forced
    【小题17】
    A．answeredB．ignoredC．hatedD．hugged
    【小题18】
    A．nothingB．somethingC．everythingD．anything
    【小题19】
    A．showedB．meant C．intendedD．expressed
    【小题20】
    A．sadB．angryC．pleasantD．joyful

    查看答案和解析>>

    如图1是“探究平面镜成像特点”的情景：
    （1）为便于观察，该实验最好在______环境中进行（选填“较明亮”或“较黑暗”）；用玻璃板代替平面镜，主要目的是______；
    （2）如果玻璃板没有放正，将对实验产生什么影响？______．
    （3）所用刻度尺的作用是便于比较像与物______关系．
    （4）选取两段完全相同的蜡烛是为了比较像与物的______关系．
    （5）移去后面的蜡烛B，并在其所在位置上放一光屏，则光屏上______接收到蜡烛烛焰的像（填“能”或“不能”）．
    （6）晶晶站在平面镜前，看到镜中自己的像，当她走近镜子时，镜中的像将______（选填“变大”“变小”或“不变”）．
    （7）小明在实验中，测出一组物距和像距相等，就得出实验结论之一：“像距与物距相等”．老师说这样得到结论不合理，你认为理由是______．
    （8）图2中是物体在平面镜中成像的情况，正确的是______
    （9）根据你的实验过程和得到的结论判断，下列说法正确的是______
    A．像的大小与蜡烛到玻璃板的距离有关
    B．蜡烛远离玻璃板过程中，蜡烛的像始终与蜡烛等大
    C．把光屏放在玻璃板后像所在的位置，像会成在光屏上
    D．用玻璃板代替平面镜是为了能在玻璃板后成一实像
    （10）好学的小军做完实验后忽然想到了一个问题，自己在镜中的像是正立的，可岸边树木在水中却成倒影，这是因为______．

    查看答案和解析>>

    My aunt bought me a bicycle on my ninth birthday. She told me to learn to ride by ___36___. But I really didn’t know___37___to ride a bike. What should I do? First, I watched the other people ride. Then I pushed out the bicycle from my house. I was ___38___ I'd fall down and hurt my knees. But I knew I had to get on it sooner or later. So I___39___ to get on just like what the other people did. But I fell off twenty___40___later. Just at that time, my aunt came out from the ___41___. She told me to practice again and again. So I got on the bike a second time, and fell off a second time. But I never gave up. I practiced a third time, a fourth time …. I could be on it ___43___every time I tried again then before, 5 minutes, ten minutes, half an hour… until I could.
    Like anything in life that you want to learn how to do or to be good at, you have to practice to ___44___it happen. Diligent practice is the key to success___45___you really want to learn to do a thing. More practice helps you to improve on the skills that you learn and ingrains （使根深蒂固）them in you until you can do it.  
    【小题1】  
    A．herselfB．yourselfC．myselfD．himself
    【小题2】
    A．how B．whatC．whereD．when
    【小题3】
    A．happyB．surprisedC．interestedD．afraid
    【小题4】  
    A．hadB．triedC．likeD．hate
    【小题5】
    A．secondsB．minutesC．hoursD．days
    【小题6】  
    A．schoolB．houseC．farmD．village
    【小题7】
    A．fifthB．fourthC．thirdD．second
    【小题8】  
    A．shorterB．longerC． saferD．dangerous
    【小题9】
    A．practiceB．enjoyC． makeD．set
    【小题10】  
    A．ifB．whenC．untilD．after

    查看答案和解析>>

    My aunt bought me a bicycle on my ninth birthday. She told me to learn to ride by ___36___. But I really didn’t know___37___to ride a bike. What should I do? First, I watched the other people ride. Then I pushed out the bicycle from my house. I was ___38___ I'd fall down and hurt my knees. But I knew I had to get on it sooner or later. So I___39___ to get on just like what the other people did. But I fell off twenty___40___later. Just at that time, my aunt came out from the ___41___. She told me to practice again and again. So I got on the bike a second time, and fell off a second time. But I never gave up. I practiced a third time, a fourth time …. I could be on it ___43___every time I tried again then before, 5 minutes, ten minutes, half an hour… until I could.
    Like anything in life that you want to learn how to do or to be good at, you have to practice to ___44___it happen. Diligent practice is the key to success___45___you really want to learn to do a thing. More practice helps you to improve on the skills that you learn and ingrains （使根深蒂固）them in you until you can do it.  
    【小题1】  
    A．herselfB．yourselfC．myselfD．himself
    【小题2】
    A．how B．whatC．whereD．when
    【小题3】
    A．happyB．surprisedC．interestedD．afraid
    【小题4】  
    A．hadB．triedC．likeD．hate
    【小题5】
    A．secondsB．minutesC．hoursD．days
    【小题6】  
    A．schoolB．houseC．farmD．village
    【小题7】
    A．fifthB．fourthC．thirdD．second
    【小题8】  
    A．shorterB．longerC． saferD．dangerous
    【小题9】
    A．practiceB．enjoyC． makeD．set
    【小题10】  
    A．ifB．whenC．untilD．after

    查看答案和解析>>


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