问题
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
B: when
C: unless
D: before
正确答案是：
同类题型
The days are approaching________the World Expo 2010 will be held in Shanghai
____ back home after the party.
Henry, the phone is ringingDo you want me to go?—No ,sit still.
The United Kingdom of Great Britain______ three main parts England, Scotland and Wales.
Why did the police ______the crowd? — Because the president’ s car ______in the street.[ ]