---Now the air in our hometown is even than it was before.
---So we must do something to stop it.
A. better
B. dirty
C. more better
D. worse
网友回答
A. better
B. dirty
C. more better
(答案→)D. worse
解析：本题考查形容词。句中出现连词than必定要用比较级，根据后句的意思是贬义，故选D.句意：——现在在我家乡的空气比以前更糟糕了。——因此我们必须做些事情阻止它。