填空题 (The university hospital's) research department (is looking for) volunteers (who) have heart disease, have undergone an open-heart surgery, have had angioplasty (血管硬化), (or a heart attack was experienced).
  • A. The university hospital's
  • B. is looking for
  • C. who
  • D. or a heart attack was experienced


  • 1、
【正确答案】 1、D    
【答案解析】本题考查平行结构的用法。将or a heart attack was experienced 改为or have experienced a heart attack，即将被动语态改为主动语态，将一般过去时改为现在完成时，以便与前文的have undergone an open-heart surgery和have had angioplasty平行。