Question

【题目】Air pollution has become than before. We must do something to stop it.

A. serious B. more serious

C. most serious D. the most serious

Answer 1

【答案】B

【解析】试题分析：句意：空气污染已经比以前变得更严重。我们必须做一些事情来阻止它。根据语境可知用形容词的比较级。serious 的比较级是more serious。结合语境，故选B。