单选题 Since last century, his family ______teachers.
  • A. are
  • B. are being
  • C. have been
  • D. were being


【正确答案】 C
【答案解析】[解析] 本句话翻译为“自从上个世纪开始，他的家里人就一直从事教师行业”，动作从过去发生，一直持续到现在，所以本句是现在完成时，只有C选项是现在完成时的用法，故选C。