问题
选择题
My sister ______ go to bed _______ my mother came back last night.
A．not until
B．doesn't; until
C．didn't; until
D．aren't; until
答案
答案：C
题目分析：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。