Question

-- When did you finish all your homework today?

--         .

A. Since my mother came back

B. Until my mother came back

C. Not until my mother came back

D. By the time my mother came back

Answer

C

【解析】

试题分析：句意：—你今天什么时候完成所有的作业的？—直到我的妈妈回来才完成。A. Since my mother came back 自从我的妈妈回来；B. Until my mother came back直到我的妈妈回来；C. Not until my mother came back直到我的妈妈回来才完成；D. By the time my mother came back到我妈妈回来为止。根据句意及语境是直到我妈妈回来才完成作业，所以用not until，故选C。

考点：考查时间状语的用法