the government has taken some measures to solve the shortage of r_英语解答

the government has taken some measures to solve the shortage of rice ,but it may
be some time _____the situation improves.
a.before b.when c.unless d.since
c 为什么不对?

人气：405 ℃　时间：2020-02-04 10:13:05

解答

It + 时间+ before 是常见结构,表示还有多少时间,某事才会发生.
如果用unless ,it may be some time unless the situation improves 除非情况改善,否则会有一段时间,句意不通!