B.
81. What is your son's age?
82. You'd better not eat much meat.
83. Because of being ill/ Mr. Hai illness yesterday, Mr. Hai/ he couldn't go to work.
84. Neither Hoa nor her aunt likes durians.
85. How much does this pear cost?
86. You aren't allowed to to smoke in this room.
87. It is not good idea (for us) to eat too much chocolate.
88. We don't have to get up early tomorrow.

C.
63. less
64. why
65. before
66. as
67. only
68. sleeping
69. same
70. not

71. Tom is interested in playing soccer.
72. If we don't hurry up, we will be late for the concert.
73. My mother is a good cook.
74. Because of not having enough money, I can't help you.
75. It will take them 3 years to build this bridge.
76. It was a eight-week trip.
77. Since this house has a big garden, Mr. Pike wants to buy it.
78. The boring film made him asleep.
79. Nobody else is better than Mai in my class
80. Lan is very good at English.

81 . what is son'age ?

C.
63. less
64. why
65. before
66. as
67. only
68. sleeping
69. same
70. not
IV. 
A.
1. Tom is interested in playing soccer.
2. If we don't hurry up, we will be late for the concert.
3. My mother is a good cook.
4. Because of not having enough money, I can't help you.
5. It will take them 3 years to build this bridge.
6. It was a eight-week trip.
7. Since this house has a big garden, Mr. Pike wants to buy it.
8. The boring film made him asleep.
9. Nobody else is better than Mai in my class.
10. Lan is very good at English.
B.
81. What is your son's age?
82. You'd better not eat much meat.
83. Because of being ill/ Mr. Hai illness yesterday, Mr. Hai/ he couldn't go to work.
84. Neither Hoa nor her aunt likes durians.
85. How much does this pear cost?
86. You aren't allowed to to smoke in this room.
87. It is not good idea (for us) to eat too much chocolate.
88. We don't have to get up early tomorrow.