1.Mrs.Green (take).......has taken.............Alice to the dentist many times.
2.Hurry up!The train (come)..........is coming.......in.
3.He (sleep)..........slept..............so he didn't understand what you said.
4.An economic critic often (follow)......follows............the war.
5.What ....was.... you (do)........doing.........at 7 p.m yesterday?
6.We didn't recognize him.He (change)...........was changing........a lot.
7.He discovered to his horror that he (eat)......had eaten..........a fly.
8.Where did you (spend)....spend.............your holiday last year?
9.He (do)...........did............nothing before he saw me.
10.All of them (sing).........were singing..........when i came.