The air in Beijing is getting much now than a few years ago.A. cleanB. cleanerC. cleanest

问题补充：

The air in Beijing is getting much now than a few years ago.

A. clean

B. cleaner

C. cleanest

D. the cleanest

答案：

A. clean

(答案→)B. cleaner

C. cleanest

D. the cleanest

解析：本句的意思是北京的空气比几年前清新多了。故用比较结构，在形容词或副词的比较级前可以用much等词来修饰。