13. My mother (wait) ________________for me when I (come) ______________ home.
14. Mrs. Smith (invite) __________________ Mrs. Quyen to have dinner while Mrs. Quyen (visit) __________________ the USA.
15. I (not want) _________________ to go with him because I (wait) ________________ for a phone call.
16. The doorbell (ring) _________________ while Tom (watch) ________________ TV.
17. It suddenly (begin) _________________ to rain while Linda (sit) ________________ in the garden.
18. The lights (go) ________________ out while we (have) _________________ dinner.

19. I was home late, but my friends (wait) ______________ when I (arrive) ___________.

20. He said that he (not drive) __________________ fast when the accident (happen) ________________.
 

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