用兆欧表测量电缆的绝缘电阻时，为防止电缆表面泄漏电流对测量精度产生影响，应将电缆的屏蔽层接至（）。

A.G端

B.E端

C.L端

D.外壳

The teacher asked the students _______.    [ ]

A. how many trees they have planted    

B. where was Yao Ming born    

C. how they will deal with the problem    

D. what happened to the monitor