问题补充:
If there are trees, the air in our city will be cleaner.
A. less, more
B. more, more
C. more, much
D. much, more
答案:
A. less, more
B. more, more
(答案→)C. more, much
D. much, more
解析:此题考查形容词的比较级,根据题干的信息可知,树木越多城市就越干净many的比较级 是more,而在比较级的前面可以用much来修饰。