单项选择题

I didn’t manage to work out the problem _______the teacher had explained how.

A．until　　　
B．unless　　　　
C．when 　　　　
D．before
<上一题 目录 下一题>
热门 试题

单项选择题
He suggested the sports meet be _______because of the bad weather.
A．put away　　　
B．put up 　　　　
C．put down　　　
D．put off
单项选择题
Where was it _____the road accident happened yesterday？
A．when　　　
B．that 　　　　
C．which　　　　
D．how
相关试题