问题 选择题

在下图电路中,AB两点间的电压保持不变,开关由断开变为合上,电流表示数将(   )

A.不变

B.变小

C.变大

D.无法确定

答案

答案:A

当开关断开时,电阻R1连接在电路中,另外两个电阻被导线短路;当开关闭合时,三个电阻是并联的,R1两端电压不变,根据的欧姆定律变形公式I=U/R故选A.

阅读理解

When Mark first arrived in Thailand, he saw an old man selling something cheap in the street of Chiang Mai. The old man was one of the poor people in Chiang Mai and there was no difference from beggars (乞丐). Most of them were some lonely old people. Their life had no support.

Mark was a kind man, so he gave some changes to him without thinking. The old man told him to pick something he liked. Mark didn’t choose anything and left.

But the old man followed him closely. AT first, Mark didn’t think a lot, just supposing he wanted to go home. But when he went out very far saw the old man still following him, he was a bit tired, thinking the old man must feel he was kind and wanted to beg more money from him.

Mark turned back and told him not to follow him because he hadn’t much money. But the old man seemed not to understand what he meant, still following him. The bag on his back made him sweat (流汗) all over.

Mark happened to meet his Thai colleague (同事) in the street and his colleague heard this. The colleague turned to ask why the old man was following his friend.

The old man said out of breath, “My son, you gave me money, but didn’t want my things, so I have to give you something. I see you are a foreigner, likely not to familiar with here. I just want to follow you and show you the way. All I can do for you is this.”

Mark was shocked. He said he didn’t know why, when he felt the old man was just like his father.

小题1:What did Mark do when he first found the old man following him?

A.He didn’t think a lot and went on walking

B.He asked the old man why he was following him

C.He was shocked and asked his colleague to come.

D.He gave him more money without thinking.小题2:The old man followed Mark closely         .

A.because he wanted to go back home

B.because he wanted to sell more things to Mark

C.because he wanted to beg more money

D.because he wanted to show Mark the way小题3:Which of the following is true according to the passage?

A.Mark didn’t like this old man at all.

B.The old man was Mark’s father.

C.The old man sold something cheap to make a living.

D.Mark didn’t give the old man anything at the beginning.小题4:How did Mark feel about the old man at last?

A.He felt the old man was kind and warm.

B.He felt pity for the old man.

C.He felt angry with the old man

D.He felt doubt if the old man was a thief.

单项选择题