Question

6. ( 2014 上海中考) Air polution has become  than

ever before. We must do something to stop it.

   A. serious   B. more serious

    C.most serious   D. the most serious

Answer 1

6. B

6. B句意:空气污染比以前更严了。我们必须做一些事情 来阻止它。由than可知使用serums的比较级more serious。