1 Does it often snow in winter?
2 I don't know the boy. I have never met him.
3 I have been cleaning my room for two hours.
4 She has been cooking lunch for an hour.
5 Those girls translated Part Two last Monday.
6 Natasha can't go. She hasn't finished her work yet.
7 They discussed everything two days ago.
8 He is not swimming. He is jumping now.
9 I think that he will be late tomorrow.
10 I have been learning the new words since ten o'clock.