87.1 spent 300 dollars buying the secondhand car.

　 I 　　　　　　the second car 　　　　　　300 dollars.

86. You cough a lot. You’d better stop smoking.

　　　 You cough a lot. You’d better 　　　　　　　　　　smoking.

85. I'm not sure w________ he can come at five or not.

B、根据第一句完成第二句，使两句意思相同或相近，每空一词

84. W___________Liu Xiang goes, there're crowds of people waiting to see him

83. Please keep q___________. My sister is doing her homework.

82. It's our duty to take part in p________our environment.

81. The boys’ football team played so c　　　　　 　that they deserved to lose.

80. The young scientist has over twenty_________(发明).

79. Hard work brings_________(成功).

78. China has the 　　　　(多) population in the world.