问题
I didn’t manage to do it _____ you had explained how.
A:until
B:unless
C:when
D:before
B:unless
C:when
D:before
正确答案是:
同类题型
When I walk_____ the classroom, all the students are listening carefully. [ ]
It is no ____ arguing with Bill because he will never change his mind.
What theywhen you got there, Tom?–Sorry, I forget.
______ does Li Lei go to school on weekdays? [ ]
You praise your son. He works harder than before. —Thanks, I will.