【单选题】测量两路电阻时,要确保所测电路已()电源,且所有大电容均已() 。
【单选题】If two uncharged objects are rubbed together and one of them acquires a positive charge then the other one ( ).
A.
also acquires a positive charge.
B.
acquires a negative charge.
C.
may or may not acquire a positive charge.
D.
may or may not acquire a negative charge.
【单选题】黑暗的夜晚我们看不清迎面走来人的面孔,但是有时候我们能凭借其走路的姿势认出是我们熟悉的人,我们主要凭借其( )来识别的。