问题 选择题

小明家新装修的餐厅里安装了一个漂亮的吊灯,你认为与吊灯的重力平衡的力

A.吊灯对电线的拉力

B.电线对天花板的拉力

C.电线对吊灯的拉力

D.天花板对电线的拉力

答案

答案:C

吊灯对电线的拉力作用在电线上,吊灯受到的重力作用在吊灯上,二力,并且方向相同,所以它们不是一对平衡力,A不符合要求;电线对天花板的拉力和吊灯受到的重力,二力的方向相同,且没有作用在同一物体上,因此不是一对平衡力,B不符合要求;电线对吊灯的拉力和吊灯受的重力,这两个力大小相等、方向相反、作用在一条直线上、作用在一个物体上,符合二力平衡的条件,因此它们是一对平衡力,C符合要求;天花板对电绳的拉力作用在电线上,吊灯受的重力作用在吊灯上,二力没有作用在同一物体上。因此不是一对平衡力。故选C。

阅读理解

阅读理解。

     A German taxi-driver, Franz Bussman, recently found a brother who was thought to have been killed

twenty years before.

     While on a walking tour with his wife, he stopped to talk to a workman. After they had gone on, Mrs

Bussman commented on the workman's close resemblance to her husband and even suggested that he

might be his brother. Franz poured scorn on the idea, pointing out that his brother had been killed in action

during the war. Though Mrs. Bussman was fully acquainted with this story, she thought that there was a

chance in a million that she might be right.

     A few days later, she sent a boy to the workman to ask him if his name was Hans Bussman, Needless

to say, the man's name was Hans Bussman and he really was Franz's long-lost brother. When the brothers

were re-united, Hans explained how it was that he was still alive.

     After having been wounded towards the end of the war, he had been sent to hospital and was separated

from his unit. The hospital had been bombed and Hans had made his way back into Western Germany on

foot. Meanwhile, his unit was lost and all records of him had been destroyed. Hans returned to his family

home, but the house had been bombed and no one in the neighborhood knew what had become of the

inhabitants. Assuming that his family had been killed during an air-raid (空袭), Hans settled down in a Village

fifty miles away where he had remained ever since.

1. Which of the following can be used as the best title of the passage?

A. Living Not Far

B. A Chance in a Million

C. Coming Back to Life

D. Back after the War

2. Why did Franz laugh at his wife's idea?

A. Because Franz believed that his brother had already been killed in the war.

B. Because Franz believed that many people looked closely like his brother.

C. Because Franz thought that his wife was just joking.

D. Because Franz believed there was a chance in a million that the workman was his brother.

3. Which of the following orders is right?

    a. He walked back to Western Germany.

    b. He was wounded when the war was coming to the end.

    c. The hospital was destroyed by bombs.

    d. He came back to his family house.

    e. He was sent to hospital. f. His unit of German didn't exist any longer.

A. b,a,e,d,f,c

B. b,e,c,a,f,d

C. b,e,a,c,d,f

D.b,c,f,d,a,e

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