19.　 We ________ (have) more than ten falls since two hours ago.

18.　 - Beautiful song, isn’t it?　 - Oh, yes. Who ________ (sing) there?

17.　 - Why are you crying, Cara?

　- I _______ (break) my mother’s expensive watch.

16.　 My mother _______ (work) in our school library.

She _______ (work) there for twenty years.

15.　 Don’t forget ________ (turn) off the light when you leave.

14.　 - Would you like to see the film with us?

- Sorry, I _________ (see) it twice. I’ll do some reading instead.

13.　 - Nice to meet you.

- Nice to meet you, too. We _________ (not see) each other for a long time.

12.　 - ______ the train _______ (arrive)?　　 - Yes, it has.

-　　 When ______ it _________(arrive)?　 　- Ten minutes ago..

11.　 The rain _______ (stop). Let’s start at once.

10.　 - Mr. Jackson has lived in Beijing for several years.

- When _______ he _______ (come) to China?

-　　 I have no idea.