to sunlight for too much time will do harm to one’s skin.
17._____ at the gate of the theatre, he found the ticket for the play was left at home.
16.By the end of last year, another new gymnasium _____ in Beijing.
15.At the meeting, a proposal that he should take charge of the project _____.
14.Teachers _____ their knowledge to their students .
13.Rainforests _____ and burned at such a speed that they will disappear from the earth in the future.