If there are trees the air in our city will be cleaner.A. fewer much B. more more C. mo

问题补充：

If there are trees, the air in our city will be cleaner.

A. fewer, much B. more, more C. more, much

答案：

解析：根据语境可知此句的含义是如果有更多的树，我们城市里的空气会更加清新。考查的形容词的比较级。Tree是可数名词，表示更多的要用more，而在形容词或副词的比较级前可以用much来修饰，故选C。