问题
You look unhappy, what’s happening, my son? —I’m wondering how long it’ll be________ we come to China again.
A:since
B:when
C:before
D:after
B:when
C:before
D:after
正确答案是：
同类题型
____ from London to Edinburgh? [ ]
Never touch my computer while I’m away． —Sorry, __________.
This morning our head teacher came to school _________ than ________ student in our class.
Excuse me, could you tell me _______? —There is a supermarket over there. You can get some there.
Sorry, Doctor Smith isn’t here right now.—May I ____ a message on his desk?