47.　 Time is _______(宝贵), so we must make full use of it.

46.　 Keep __________(练习) it, and you'll master the spirit of it.

45.　 We've got to be ____________(实际) and buy only what we need.

44.　 When did the president come into ____________(当权)?

43.　 Don't play with fire at a place where gun _________(火药) is stored.

42.　 These ______(土豆) has gone bad.

41.　 If __________,(可能)he will pick you up.

40.　 Who is in _________(拥有) of the property?

39.　 He applied for the _________(职位) of assistant manager.

38. Measures should be taken to stop the earth from being ________(污染)