下列投影图中采用平行直角投影法的是（）。A、AB、BC、CD、D_爱下问搜题

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问题单项选择题

下列投影图中采用平行直角投影法的是（）。

A、A

B、B

C、C

D、D

答案

参考答案：B

填空题

用所给单词的适当形式填空，使短文正确，通顺，每词限用一次。

like, second, make, be, watch, eye, danger, and, in, little

     I think watching TV is not good for students. First, children   1   different from adults(成人).It's true that
students   2 relaxing by watching TV. However , the   3 thing for students is that they just can't take their
   4 off the screen (屏幕).They will go on watching TV for hours   5 hours. It's very bad for their eyes.
  6 , many students have the habit of   7 too much TV. Then they will have   8 time for sports. Third, some
TV programs are not suitable (合适的) for students.Finally,too much TV can   9 students weak (差的) in
reading. They will lose interest   10 reading, which I think is a terrible thing.

不定项选择

两带电荷量不等的绝缘金属小球，当相隔某一定距离时，其相互作用力为，现将两小球接触后分开并保持原有距离，它们之间的相互作用力为，下列说法正确的是[ ]

A．若，则两个小球所带电性必相反　　

B．若，则两个小球所带电性必相同　　

C．是不可能的　　　　　

D．以上三种说法都不对