Question

They didn’t go to bed ________ they finished their homework.

A．when

B．because

C．until

D．if

Answer 1

C

试题分析：句意：他们一直到完成他们的家庭作业才去睡觉。When当……时；because因为；until直到，常与not构成固定句型not···until直到……才； if如果。所以选C。