---Now the air in our hometown is even than it was before.-So we must do something to s

问题补充：

---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

答案：

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。