56. A. should               B. might                           C. ought（应当） D. would

55. A. had                 B. grew                            C. played            D. saved

54. A. free                B. busy                            C. happy              D. angry

53. A. waste               B. take                            C. cost                D. spend

52. A. among                B. through                         C. during            D. on

51. A. strange               B. unforgettable（不可忘记）C. natural            D. sad

49. The prices of buildings __________ day by day and many people can t afford to buy them.

48. We should spend more time working. We shouldn't _______ time playing computer games.

47. We must save our money. After all, we have 10 days left. I can't ______ how we would live without money.