16. She likes everything to be in place整洁；恰当 _before_______ she starts to work.

15. It was not ___until_____ he took off his eyeglasses that I recognized him.

14. I waited ___until_____ he came back.

13. I haven't seen him ____since_____ he moved to the other side of the town.

12. _____After____ the work was done, we sat down to sum up experience总结经验.

11. He had learned Chinese ___before______ he came to China.

10. I listen to the recorder ____when_____ I have time.

9. Henry is in charge of the office __while/when______ Mr. Smith is away.

8. He learned to speak German ___when/while______ he was in Berlin.

7. We'll go to the country at the beginning of June, ____when_____ the summer harvest will start.