50.Without the sun＇s light ( )the earth＇s surface， no life could exist on the earth.

45.You can eat food free in my restaurant ()you like.

44.Americans eat ()vegetables per person today as they did in 1910.

43.So instructive ()the student wanted to see it again.

42.A library with five thousand books ()to the nation as a gift.

41.Someone is ringing the doorbell.Go and see().

40.He wrote a letter to me ()that his trip to Japan had been put off because of
the bad weather

39.Lessons ()easily were soon forgotten.

38.In order not to be disturbed， I spent three hours ()in my study.

37.We are looking forward ()a trip to your country.

36.It’s no use()your chickens before they are hatched.