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问题 单项选择题

下列哪些并非不得超车的情形？（）

A.前车为政府人员用车

B.前车正在左转弯、掉头、超车的；与对面来车有会车可能的

C.行经铁路道口，交叉路口、窄桥、弯道、陡坡、隧道、人行

D.前车为执行紧急任务的警车、消防车、救护车、工程救险

答案

参考答案：A

阅读理解

During the day we work and play，and at night we sleep. Our body rests when we sleep. In the morning we are ready to work and play again. Our body grows most when we are asleep. Children who are tired usually need sleep. We can get better at our lessons after having plenty of rest. Boys and girls who are eight or nine years old need ten hours of sleep every night. Our body needs plenty of air when we are asleep. If we do not get enough fresh air, we will feel tired when we wake up. While in bed we must not cover(覆盖) our head，our lungs need to get enough fresh air. If we open our windows at night，we can have plenty of fresh air. Cool air is better than warm air.

小题1:Our body grows most while we are _______.

A.eating    B.playing   C.sleeping 

小题2:Too little sleep makes us _______.

A.tired B.hungry    C.happy

小题3:—What may cause us to feel tired in the morning?

—_______ during the sleep.

A.Too much air      B.Not enough fresh air

C.Too much cold air    

小题4:How many hours of sleep should 9-year-old children have every night?

A.8 hours.  B.9 hours.  C.10 hours.

小题5:What do the lungs need most?

A.Fresh air.    B. Exercise.    C.Warm air.
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问答题 计算题

如图所示，点光源S位于光屏AB的右方，平面镜MN初始时与光屏AB平行，点光源S发出的光从光屏AB上的小孔P射到平面镜上的O点，SO⊥MN，PO=d，今将平面镜绕着过O点的轴逆时针方向匀速转动，角速度为ω，求：

（1）从初始位置开始转过30°角的过程中，光线SO经平面镜反射落在光屏AB上的斑点Q移动的平均速度。

（2）平面镜转到与初始位置夹30°角的瞬间，斑点在光屏上移动的瞬时速度。
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