Now the air in our city is than it used to be. Something must be done to stop it.A. very

问题补充：

Now the air in our city is than it used to be. Something must be done to stop it.

A. very good

B. much better

C. rather bad

D. even worse

答案：

A. very good

B. much better

C. rather bad

(答案→)D. even worse

解析：形容词或副词的比较级前可以用much，even等次 来修饰，以加强语气。根据语境可知城市的空气质量是更加糟糕，故用D。