单选题 —Did Nancy come for the meeting last night?
—No. She was so tired that she soon ______ in her room.
  • A. fell behind
  • B. fell asleep
  • C. fell off


【正确答案】 B
【答案解析】fell asleep意为“睡着了”，fell behind意为“落后”，fell off意为“掉落”。