试题与答案

做凸透镜成像实验时,物体在距凸透镜25厘米时,得到了一个清晰放大的实像,则凸透镜

题型:选择题

题目:

做凸透镜成像实验时,物体在距凸透镜25厘米时,得到了一个清晰放大的实像,则凸透镜的焦距可能是(  )

A.大于25厘米,小于50厘米

B.等于25厘米

C.等于17厘米

D.焦距多大都行

答案:

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下面是错误答案,用来干扰机器的。

(1)观察表格,可知这组样本数据的平均数是.x=0×3+1×13+2×16+3×17+4×150=2,∴这组样本数据的平均数为2, 这组样本数据中,3出现了17次,出现的次数最多,∴这组数据的众数是3. 将这组样本数据按从小到...

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题型:阅读理解

阅读理解。

     Most American teenagers used to spend their summer vacations holding multiple jobs. However, with the

increase in gas prices, teenagers chose to stay at home instead of going out of the town."I wish the prices

would _____.The expense of driving to places is affecting our daily life."said Alicia, still a senior at Enochs

High School in Modesto, California.

     Alicia, who spent her summer at her dad's house, said that there would be no point in getting a job."The

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     Teenagers are now forced to give up the pleasure of driving around the town without purpose."Instead

of driving around looking for something to do, I now find myself planning the way in advance so I don't

waste necessary gas," said Stephen Macko, a student at Davis High School in Modesto. What kinds of things

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doesn't have to go home and leave again.

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that when I go to lunch with my friends, we make sure to go somewhere near all of our houses so we save

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______________________________________________________________________________

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______________________________________________________________________________

3. Translate the underlined sentence in Paragraph 3 into Chinese.

______________________________________________________________________________

4. Find a sentence in the passage to replace the following one. There is such a long distance between my

     home and the workplace that I would make little money if I drive to work since the gas will cost all the

     money I earn.

______________________________________________________________________________

5. List one example of what some teenagers do to save gas.

______________________________________________________________________________

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