title: 英语选择160516.Ironhasanimportantrol 
desc: 16. Iron has an important role to play in the _____working of the human body and is val (至关
  
  要的) to healthy living.
  
       A) efficient             B) favorite          C) primary        D) current
  
  5. He might as well have picked a family _____out of the telephone book a16. Iron has an important role to play in the _____working of the human body and is val (至关
  
  要的) to healthy living.
  
       A) efficient             B) favorite          C) primary        D) current
  
  5. He might as well have picked a family _____out of the telephone book and stayed with them.
  
       A) at random           B) at a time          C) after all        D) 
answer: C. primary
  A. at random