问题
选择题
The air in mountain areas is ____ that in big cities.
A.as fresh as
B.fresher than
C.as dirty as
D.dirtier than
答案
答案:B
此题考察形容词的比较级或原级。fresher than... 通常乡村的空气要比城市中的空气新鲜, 所以排除A,C, D选项, 虽然A选项本身结构是正确的。