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问题 选择题
如果把
3x-2y
5x+7y
中的x，y都扩大10倍，则分式的值（　　）
A．扩大10倍B．不变
C．由x，y的值确定D．缩小到原来的
1
10
答案

分别用10x和10y去代换原分式中的x和y，得

3x-2y
5x+7y
=
30x-20y
50x+70y
=
10(3x-2y)
10(5x+7y)
=
3x-2y
5x+7y
，则分式的值不变．

故选B．

问答题 简答题

什么是辐射？分为几大类？
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听力题

填入一个适当的词补全对话，每空一词

A: How are you, Jane?

B: Fine, __小题1:__. And you?

A: Very well. I’ve heard that a foreign teacher is helping the people in Ya’an. __小题2:__ don’t we do something for others?

B: That’s a good idea. Do you have any plans for it?

A: I’m going to give my old clothes to the children in the countryside together __小题3:__ my father. Would you like to join us?

B: __小题4:__ love to. When shall we go there?

A: I have time on __小题5:__ Friday and Saturday. How about you?

B: I’m busy on Friday but __小题6:__ on Saturday morning. Shall we start at 10 o’clock?

A: Sorry, I’m afraid not. Let’s __小题7:__ it 10:30 on Saturday.

B: That would be fine. Shall we meet at the school gate?

A: All right.
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