1.i am busy now,so i can't help____the machine
a.to repair b.to have repaired
c.repairing d.fixing
2.we agreed____here but so far she hasn't turned up yet
a.having met b.meeting c.to meet d.to have meet
3.go on___the other exercise after you have finished this one.
a.to do b.doing c.with d.to be doing
4.mike,you must get your study room ___after lunch.
a.being cleaned b.to clean c.cleaning d.cleaned
都要告诉我原因的