We must take measures to stop various kinds of pollution Wap版

试题详情及答案解析

We must take measures to stop various kinds of pollution ______ the environment gets worse.

A．unless	B．until
C．before	D．when

答案：C

试题分析：考查状语从句连词辨析。A除非，如果不；B直到…才；C在…之前；D当…时；句意：在环境变得更糟糕之前我们必须采取行动来阻止各种污染。根据句意可知C正确。
考点：考查状语从句连词辨析