When did your father come back last night?He didn’t come back he finished all the

问题补充：

--- When did your father come back last night?

--- He didn’t come back he finished all the work.

A. until

B. while

C. if

D. unless

答案：

(答案→)A. until

B. while

C. if

D. unless

解析：until直到；while然而，当……时； if是否，如果；unless除非，如果不；句意：昨天晚上你的父亲什么时候回来的？——直到他完成所有的工作，他才回来。结合语境可知选A。