Only _____ a human being. [ ]

A. when is it hungry a lion will attack

B. when it is hungry a lion will attack

C. when it is hungry will a lion attack

D. when is it hungry will a lion attack

以下哪项减少“碘过敏反应”的发生，无帮助()

A．高危患者避免使用含碘造影剂 

B．减少造影剂用量 

C．检查前做碘过敏试验 

D．选用离子型对比剂 

E．选用非离子型对比剂