Question

【题目】—Mark, you look so tired.

—Oh, I worked ____ it was 12 o’clock last night.

A. unless B. after C. till D. as

Answer 1

【答案】C

【解析】句意：-马克，你看起来很累。-哦，我一直工作到昨晚十二点。A. unless“除非”；B. after“在…之后”；C. till“直到…”；D. as“由于”。故选C。