8. -The light in his room is still on. Do you know____________?
-In order to prepare for the coming exam.
A. if he works hard B. why he stays up so late
C. why is he so busy D. when he will stop working
7. The teachers____________ the office for a few minutes when we arrived. We didn’t meet them.
A. had been away from B. had left
C. have been away from D. have left
6. Don’t discuss the problems with your partner unless you____________ to do so.
A. ask B. are asked C. will ask D. will be asked
5. The music in the supermarket sounded so____________ that I wanted to leave at once.
A. soft B. wonderful C. friendly D. noisy
4. -Mark speaks English well, but you____________ him.
-Thank you. .
A. speak as badly as B. speak worse than
C. don’t speak so badly as D. speak much better than
3. -Your French is so good. How long have you been in France?
-____________I was five.
A. Until B. Since C. When D. Before
2. -____________I borrow these magazines?
-Sorry, only the magazines over there can be borrowed.
A. Must B. Would C. May D. Need
从A、B、C、D四个选项中,选出可以填入空白处的最佳选项。
1. -Which would you like, Coke or tea?
-____________. I prefer coffee.
A. Neither B. Both C. Either D. None
19.
半径分别为r和2r的两个质量不计的圆盘,共轴固定连结在一起,可以绕水平轴O无摩擦转动,大圆盘的边缘上固定有一个质量为m的质点,小圆盘上绕有细绳.开始时圆盘静止, 质点处在水平轴O的正下方位置.现以水平恒力F拉细绳, 使两圆盘转动,若恒力 F=mg,两圆盘转过的角度θ= 时,质点m的速度最大.若圆盘转过的最大角度θ=π/3,则此时恒力F= 。
答案
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[1D 2BC 3C 4BC 5B 6BCD7CD 8AC 9C 10B 11BCD]
18.一内壁光滑的环形细圆管,位于竖直平面内,环的半径为R(比细管的半径大得多).在圆管中有两个直径与细管内径相同的小球(可视为质点), A球的质量为m 1,B球的质量为m 2,它们沿环形圆管顺时针运动,经过最低点时的速度都为v 0.设A球运动到最低点时,B球恰好运动到最高点.若要此时两球作用于圆管的合外力为零,那么m 1、m 2、R与v 0应满足的关系式是 .
答案:
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