单选题 The secret agent kept looking back because he was afraid of ______.
  • A. followed
  • B. being followed
  • C. having followed
  • D. having been followed


【正确答案】 B
【答案解析】[分析] of是介词，其后接动名词。由于follow和主语he是被动关系，所以用动名词的被动式。D项是动名词的完成被动式，表示此动作与主语是被动关系且先于谓语动作发生，不符合本题题意。