It was at the very beginning _____ Mr. Fox made the decision _____ we should send more fire-fighters there.

A．when; which

B．where; that

C．that; that

D．then; so

关于心导管检查造影剂的选择及用法，下列叙述正确的是（）

A.心血管造影选非离子型造影剂，颈动脉、肺动脉选离子型造影剂

B.高血压病人应选用离子型造影剂，有造影剂过敏史者选非离子型造影剂

C.每次用量1～2ml/kg

D.注射时间必须超过2个心动周期

E.造影剂选用低浓度造影剂