单选题 ______ from his family for a long time, Mark was very worried about them.
  • A. Not hearing
  • B. Not having heard
  • C. Not to hear
  • D. To have not heard
【正确答案】 B
【答案解析】[解析] Not having heard是分词的完成式，表示在主句谓语动词之前所发生的事情，在句中作原因状语。