— What______useful dictionary for beginners of English! Where did you get it?

— I bought it in the bookshop.

A．a

B．an

C．the

D．/

下列哪项处理不妥

A．吸氧、镇静

B．服用地高辛

C．用利尿剂

D．静脉注射西地兰

E．使用血管活性药物