问题 选择题

如图所示,三个电压表用满偏电流相同的电流表改装而成,已知电压表V1的示数为8v,电压表V3的示数为5V,则关于电压表V2的示数,下列判定中正确的是(  )

A.电压表V2的示数必为3V

B.电压表V2的示数必为5V

C.若三个电压表量程相同,则电压表V2的示数必为3V

D.即使三个电压表量程相同,电压表V2的示数也可能不等于3V

答案

A、B,电压表V2与电阻串联,串联的总电压等于V3的示数5V,所以V2的示数必定小于5V,由于三个电压表量程关系未知,无法确定其示数.故AB错误.

C、D,三个电压表用满偏电流相同的电流表改装而成,满偏电流相等,若电压量程相同,则三个电压表的内阻相等,设为R.

通过电压表V2的电流为I2=I1-I3=

U1
R
-
U3
R
=
U1-U3
R
=
3
R

电压表V2的示数为U2=I2R=3V.故C正确,D错误.

故选C

填空题

Part 4


Questions 26-45


·Read the following passage and choose the best word for each space.
·For questions 26-45, mark one letter A, B, C or D on the Answer Sheet.
During the past ten years (26) attention has been given to "telling it like it is". My impression is that this devotion to (27) one’s mind has more often led to hurt feelings and ruined relationships than (28) great joy.
I think we generally agree that never expressing real feelings and (29) all less-than-lovely thoughts about each other always leads to constructive communication. It’s a great (30) to allow ourselves to admit our human weaknesses and pursue more honest relationships with others. (31) we need to keep a balance between telling it all and telling nothing.
Recently I received a letter from a mother who had been (32) by her son to attend a weekend meeting with him. Under pressure from the group, her defenses cracked and she heard herself (33) her son for the first time that he (34) an accident—that she hadn’t been planning to have a child. He (35) told her that he couldn’t recall a single day in his childhood that he’d been happy. We cried and (36) ; I thought telling the truth had been good for us. But the trouble is, it wasn’t the whole truth. By the time Tommy was born I did want him, and at (37) he was happy. Ever since that day, we (38) . by some terrible feelings we exchanged. I must admit I’ve (39) the conclusion that some things are better left uncovered. Honesty is a fine policy, but we need a new sense of (40) . Disclosing is not a solution to every problem (41) even an end in itself. It’s useful under some circumstances and terribly hurtful under (42) . It’s a good idea, I think, to bite your (43) for ten or fifteen minutes before saying what’s (44) your mind. Try to decide whether it’s going to open up new and better ways of communication or (45) wounds that may never heal.

A.dissuaded

B.persuaded

C.convinced

D.convicted

单项选择题