Question

【题目】- Tom, you look tired this morning. What's wrong?
- I was busy and I didn't go to bed _________ 12 o'clock last night
A.until
B.when
C.though
D.unless

Answer 1

【答案】A
【解析】句意：——Tom，你今天上午看起来很累，怎么啦？——我很忙，昨晚12点才睡觉。not until直到……才，故选A。