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问题 单项选择题

一个质点同时在几个力作用下的位移为：，其中一个力为恒力，则此力在该位移过程中所作的功为（）

A．-67J

B．17J

C．67J

D．91J

答案

参考答案：C

解析：

由功的计算公式W=F·S可得：此力在该位移过程中所作的功为：

翻译题

根据句子意思，用括号中所给汉语提示或英语单词的适当形式填空。在答题卡标有题号的横线上，写出空缺处所填单词的正确形式。（每空一词）

小题1:The witness was asked to      the suspect. (描述)

小题2:He is hard-working and always uses his free time        (明智).

小题3:I have       （决定）to write a complaint letter for my broken bike.

小题4:His attractive performance on the stage comes from           (日常)practice.

小题5:The coldest month in Yangzhou is January while the        (热),month is July.

小题6:If you want to stay     (health), you’d better go to bed early and do some exercise.

小题7:He devoted all his efforts to       (educate) children.

小题8:Alice found       (she) alone in the hole. She was very lonely.

小题9:Miss Wang found Jane was too        (care)because of so many mistakes in the exercise.

小题10:Do you know the        (interview)names from CCTV? I am not familiar with them.
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单项选择题

M指天然气的视相对分子量，则M/38.964计算的是天然气的（）。

A、视密度

B、相对密度

C、摩尔分数

D、质量分数
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