49. Birds have feathers ________ in cold weather.

      A. to keep them warm                                  B. to wash their faces

      C. to move fast                                D. to keep young

48. If weather changes, birds’ temperature ________.

      A. comes down                                         B. changes a lot     

C. goes down                                            D. stays about the same

46. A. turned on            B. turned down             C. played                      D. enjoyed 

45. A. roommate           B. classmate                  C. neighbor                  D. team

44. A. So                      B. And                         C. As                           D. But

43. A. only                   B. still                          C. already                     D. yet

42. A. knocked              B. tried                        C. pushed                     D. broke

41. A. Find                   B. Book                       C. Enter                       D. See

40. A. new                    B. good                        C. late                          D. bad