单选题 She was so interested in the book that she______it for three hours before she realized it.
  • [A] read
  • [B] would have read
  • [C] was reading
  • [D] had read


【正确答案】 D
【答案解析】后面的for three hours before she realized it提示要用过去完成时态，表示在过去某一时刻之前动作已经完成。