6.On our way to Beijing, we visited Xi’an, a city of two million ____, and stayed there for two days.
A. insects
B. human
C. inhabitants
D. flights

7.One of the main reasons for air pollution is that many cars ____ smoke into the atmosphere.
A. gather
B. hire
C. discharge
D. escape

8.Don’t forget to ____ to let us know you arrived safely.
A. cable
B. cage
C. border
D. bay

9.She gave him a ____ that she could not come to his party.
A. mistress
B. shoot
C. neck
D. hint

10.When the temperature is below zero, water will ____.
A. freeze
B. virtue
C. sink
D. seek

答案：6. C 居民
在去北京的路上，我们去了趟西安在那呆了两天，西安有两百万人口。
7. C 排放
空气污染的一个主要原因是汽车排放尾气。
8. A cable 打电报
不要忘了发电报告诉我们你安全抵达。
9. D 暗示
A主妇,女主人,情妇
她暗示他去不了聚会。
10.A 结冰
温度低于零度时，水就会结冰。