单选题 At first he didn't realize that he had succeeded.
  • A. know
  • B. find out
  • C. recognize
  • D. look into


【正确答案】 A
【答案解析】[解析] realize和know都可以表示“知道、了解”；find out：发现(事实、原因等)；recognize：认出、识别；look into：调查、观察。