药物能在预定时间内自动以预定速度释放，使血药浓度长时间恒定维持在有效浓度范围内的制剂（）

A．缓释制剂

B．被动靶向制剂

C．物理化学靶向制剂

D．控释制剂

E．主动靶向制剂

There is such a problem _____ we all should _____．

A．as; pay attention to it

B．that; attract our attention

C．as; pay attention to

D．that; attract our attention to it