单选题 The old man, ______ abroad for twenty years, is on the way back to his motherland.
  • A. to Work
  • B. working
  • C. to have worked
  • D. having worked
【正确答案】 D
【答案解析】[解析] 因work abroad for twenty years发生在谓语动作(返回祖国)之前，所以用现在分词的完成式。