g sentences and decide what forms of the given verbs should be used. （10%）
51. What do you think the children __________ （do）when we get home?
52. He gave up hope of passing the examination，since he __________ （already fail）it twice.
53. It’s getting rather late. It’s time we __________ （go）.
54. How long __________ you __________ （be） in your present job?
55. The flat would be all right if people above us __________ （not be） so noisy.
56. The house is a good buy. It was just painted and __________ （have） all the conveniences.
57. I asked them to be quite. I __________ （try） to hear what the man was saying.
58. When I leave the school next week，I __________ （teach） this course for ten years.
59. We __________ （leave） for Beijing on Monday.
60. We’ll go for a picnic if it __________ （be） fine tomorrow.

IV. Read the following incomplete sentences and decide what non-finite forms of the given verbs should be used. （10%）
61. We got tired of waiting for the weather to clear and finally decided __________ （set） out in the rain.
62. He was surprised to find his room thoroughly __________ （clean）.
63. __________ （tell）what English food is like，they decided not to spend their holiday in England.
64. Hampton Court is well worth __________ （take） the trouble to visit.
65. These students are quick at learning. We’ll have them __________ （train） in new methods.
66. The murderer is said __________ （catch） yesterday.
67. They appear __________ （injure） in the accident.
68. I don’t enjoy __________ （go） to the dentist.
69. A good administrator must know how __________ （be）firm.
70. He resented __________ （ask） to wait.