图示电路中，电压源U_S2单独作用时，电流源端电雎分量U'_1S为（）。

A．U_S2-I_SR₂

B．U_S2

C．0

D．I_SR₂

缺词填空

Hi, I’m Jim Green. I was b__1__ in New York. I am an A__2__. Now I live in China. I am in Beijing with my  p__3__. My father is a w__4__. He works in a factory. My  mother works in a school, and she  a__5__ works hard. But she is not a t__6__. She works in a l__7__. There are many books in it. I have a t__8__ sister. Her mane is Alice. We are in the s__9__ school, but in d__10__ classes. We both like reading.