一个摩托车驾驶员以每小时20千米的速度行了3小时．然后，立即沿

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问题解答题

一个摩托车驾驶员以每小时20千米的速度行了3小时．然后，立即沿原路返回，每小时行30千米．这辆摩托车往返的平均速度是每小时多少千米？

答案

20×3×2÷（3+20×3÷30），

=120÷5，

=24（千米）；

答：这辆摩托车往返的平均速度是每小时24千米．

选择题

It was _____ computer games that cost the boy a lot of time that he ought to have spent on his lessons.

A．to have played

B．playing

C．played

D．having played

排序题

将下列句子按正确顺序排列,组成对话。

A. Do you have a basketball?

B. Yes,I do. Let me ask my mother first.

C. Hello, Linda. Let's play baseball.

D.I like comedies. Do you like comedies?

E. Well, let's go to a movie.

F. That sounds good.

G. What kind of movies do you like?

H. No,I don't.

I. It's boring. Let's play basketball.

J．OK.

1._____2. _____3. _____4. _____5. _____ 6. _____7. _____8. _____9. _____10. _____