Correct:
1/I (see) a car accident while I (wait) for you on this corner yesterday
2/Miss Lan (be) principal of our school since last year
3/Mr Khai (teach) at this school since he(graduate)in 2000
4/I(meet)an old friend three days ago
5/Yesterday,the police(report)that they(capture)the thief
6/My friend(thank)me for what I do for him before
7/Someone(steal)my handbag on the bus recently
8/Last month,I (be) in the hospital for 10 days
9/(Not call)me in the afternoon.I often(be)away in the afternoon
10/Lan(ride) that electric bike since I (know) her
11/People (speak) English in most of Canada
12/The peg dog(wag)histail when ever he (see) me
13/What you (do)when I (rang) you last night?
14/Up to now,I (never see)such a fast man
15/They (sell)all the tickets when we (get) three last week
16/I think he leave as soon as he (know) the news
17/She(play) the piano when our guests (arrive)last night
18/Where you (spend)your holidy next summer?