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】

【解析】B

试题分析：句意：空气污染已经变得比以前更加严重。我们必须做些事情来阻止它。than用于比较级的句子中，形容词应该用比较级的形式，serious的比较级为more serious，故答案为B。