题干

2011年11月01日5时58分07秒,我国成功发射神州八号飞船,它将与天宫一号实现空中对接,从而建立我国第一个空间实验室。假如神舟八号与天宫一号对接前所处的轨道如图甲所示,图乙是它们在轨道上即将对接时的模拟图。当它们处于图甲所示的轨道运行时,下列说法正确的是

A:神舟八号的加速度比天宫一号的大

B:神舟八号的运行速度比天宫一号的小

C:神舟八号的运行周期比天宫一号的长

D:“神舟八号”从图示轨道运动到与“天宫一号”对接过程中,机械能守恒

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答案(点此获取答案解析)

A

同类题4

阅读下列短文,从每题所给的四个选项(A、B、C和D)中选出最佳选项。

A

    When I was a little kid, a father was like the light in the fridge. Every house had one, but no one really knew what either of them did when the door was shut.

    My dad left the house every morning and always seemed glad to see every one again at night. He opened the jar of pickles when no one else at home could. He was the only one in the house who wasn't afraid to go into the basement by himself. 

    Whenever it rained, he got into the car and brought it around to the door. When anyone was sick, he went out to get the prescription(处方) filled. He set mousetraps. He cut back the roses so the thorns(刺) wouldn't hurt you when you came to the front door. He oiled my roller skates, and they went faster. When I got my bike, he ran alongside me for at least a thousand miles until I got the hang of it. He signed all my report and cards. He took a lot of pictures, but was never in them. He tightened up Mother's sagging(松垂的) clothesline every week or so.

    I was afraid of everyone else's father, but not my own. 

    Whenever I played house(玩过家家), the mother doll had a lot to do. I never knew what to do with the daddy doll, so I had him say, “I'm going off to work now,” and threw him under the bed.

    When I was nine years old, my father didn't get up one morning and go to work, he went to the hospital and died the next day. 

    There were a lot of people in the house who brought all kinds of good food and cakes. We had never had so much company before.   

    He never did anything; I didn't know his leaving would hurt so much.