Question

【题目】The government has taken some measures to reduce the smog, but it may be some time _____ the situation improves.

A. since B. when

C. unless D. before

Answer 1

【答案】D

【解析】试题分析:句意：政府已经采取了一些措施去解决水的短缺问题，但是可能还要一段时间后情况才会有所好转。A自从；B当….时候；C除非；D在之前。固定句型：it may/ will be +时间段+before 从句，“还要一段时间才能…,选D。