1) May I (ask) you to take off your hat?
2) She asked me if it was safe to turn on the light.
3) I am afraid it will not have stopped raining by the morning.
4) Don't scold her: the task was too difficult for her, that's why she made rather many mistakes.
5) If they don't miss the rain, they will arrive in time.
6) Why isn't he here yet? What has happened? He missed the rain.
7) He has been doing very hard work. that's why he looks so tired now.