The boy go to bed his mother came back.
A. won’t ; until
B. didn’t ; until
C. will ; until
D. won’t ; before
网友回答
A. won’t ; until
(答案→)B. didn’t ; until
C. will ; until
D. won’t ; before
解析：考查not…until结构。据his mother came back应用一般过去式，选B.直到母亲回来，这个男孩才上床睡觉。