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问题 单项选择题

预防接种是（）

A.控制传染源

B.切断传播途径

C.保护易感人群

D.包括ABC

答案

参考答案：C

计算题

（10分）一质量为m1的小球A与另一质量为m2的静止小球B发生正碰。实验中测出碰撞后小球B的速度为v2，求小球A原来的速度v0的最大值和最小值分别是多少？

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阅读理解
阅读短文，从方框中选出适当的动词，并用其适当形式填空。有的需要加助动词或不定式符号。
believe,   read,   interest,   careful,   bored
     Some teenagers think that newspapers are 1______ and only for adults. But that's not true. There are
many interesting stories in the paper. You just need to make clear what you are looking at."I spend about half
an hour 2______ newspapers every day," said 15-year-old Gao Ming from Beijing."I'm 3______ in things
happening at school." School news is just one kind of news story in newspapers. There's also world news:
from international problems to pop stars. Read the newspaper 4______, we'll find much information. But
we'd better not 5______ the advertisement.
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