1.He refused to give any reasons for his action.
2.May she share your umbrella together with you?
3.What is your purpose in going to Canada?
4.It was crazy of you to go skating on such thin ice.
5.He had almost entirely forgotten what he had done.
6.You must trust me because I am speaking the truth.
7.Do not disturb your father ,he is busy.
8.columbus discovered America in 1492.
9.The sun was hiden by the clouds.
10.It is not in my possibility to help you.
11.We must do as much as we can to make our country more beautiful.
12.The teacher asked him to write down his story in the paper.
10题实在想不出来了.可能有错