单选题 I don's know ______ or not.
  • A.whether he is at home
  • B.if he is at home
  • C.that he is at home
  • D.whether is he at home
【正确答案】 A
【答案解析】[解析] 动词know后引导宾语从句，句意为：我不知道他是否在家。