问题 多选题

下列说法正确的是[ ]

A. 测定某恒星特定元素发出光的频率,对比地球上该元素的发光频率,可以推算该恒星远离地球的速度

B. 无线电波没有偏振现象

C. 红外线比无线电波更容易发生干涉和衍射现象

D. 在一个确定的参考系中观测,运动物体上物理过程的时间进程跟物体运动速度有关

答案

AD

阅读理解

根据短文内容,选择正确答案。

     My friend Bob has an interesting hobby. He likes collecting stamps. He spends a lot of time on his

stamp collection after school hours. Now he has hundreds of stamps from all over the world.

     Bob likes stamps with pictures of animals and plants on them. In this way, he learns the names of

many animals and plants. He also borrows books on animals and plants from his school library. He learns

a lot from them.

     Sometimes Bob has many stamps of the same kind. He gives some of them to his friends. And they

give him others in return (回报).

     Bob often writes to his friends in many countries. He sends them stamps of his country. In return, they

send him stamps of their countries. 

     Bob thinks collecting stamps can bring him much knowledge, pleasure and happiness. And he can

make more friends from all over the world.

1. Bob spend a lot of time on his hobby ______.

A. during his holiday

B. after school hours

C. during school hours

D. on Sundays

2. Bob learns a lot about animals and plants from ______.

A. his teachers

B. his friends

C. his stamps      

D. his classmates

3. When Bob has stamps of the same kind, he ______.

A. sells them to his friends

B. throws then away

C. keeps them for himself

D. sends some of them to his friends

4. Bob often sends some stamps to his friends in many countries, and the friends ______.

A. send him other stamps in return

B. write him letters for thanks

C. give him some money

D. send him some foreign coins

5. Collecting stamps can make Bob ______.

A. very happy

B. learn much knowledge

C. make more friends

D. A, B and C

判断题