5.在老师的帮助下，我赶上了其他同学。

______ _______ _______ _______ my teacher ,I caught up with the other students.

4.因为家庭贫困，父亲不得不退了学。

My father had to _______ ______ ________ ________because his family was very poor .

3.你到过多少个国家？

_______ _______ countries ______ you _______to ?

2.太阳系只是银河的一小部分而已。

The solar system is only _______ ________ _______ ______ the Milky Way.

1. 你曾经梦想过到太空旅行吗？

Have you _____ ______ ______ _______ in space?

5.Tom has learned to fly a model plane .(改为一般疑问句)

______ Tom _______ to fly a model plane?

4.Mr. Green isn’t here. He is in the library.(改为同义句)

　Mr. Green _______ _______ _______ the library.

3.They have known each other for thirty years.(画线部分提问)

______ ______ have they _______ each other?

2.They have found life on Mars.(改为否定句)

They _______ found life on Mars________.