问题补充:
My sister go to bed my mother came back last night.
A. not until
B. doesn ; until
C. didn ; until
D. aren ; until
答案:
A. not until
B. doesn ; until
(答案→)C. didn ; until
D. aren ; until
解析:句意:我妹妹昨晚知道我妈妈回来才上床睡觉。固定短语not…until…直到……才……,last night昨晚,是一般过去时态,所以此句借助助动词did,故选C。