1. He _____________ (collect) 300 pictures since 5 years ago.

2. My father came into the bedroom while I ___________ (dance).

3. If the old _________ (want) to cross a street, he must wait for the green light.

4. American fast food seems ____________ (be) the most popular in the world.

5. Can you tell me the _______________ (different) between the two pictures?

6. She got the good job ______________ (success).

7. The scientist said that the moon_________(go) around the earth.

8. We are looking forward to ______________ (visit) the great wall.