The government has taken some measures to solve the shortage of electricity, but

The government has taken some measures to solve the shortage of electricity, but it may be some time _______ the situation improves.   

       A．since                      B．when                      C．unless                     D．before

试题答案

D

解析:

考查连词用法。“It be+一段时间+before…”是固定结构，该结构的意思是“要过……（长）时间才……”。when“．．．．．．的时候”；since“从．．．．．．开始”；unless“除非”；根据题意D最佳。