—Where did you get this book?

—I picked it up from a second-hand bookshop if you ______ know.

A．must

B．will

C．can

D．shall

可减慢心率、减弱心肌收缩力、减少心排血量、降低血浆肾素活性的降压药物是（）

A.哌唑嗪

B.卡维地洛

C.引哒帕胺

D.贝那普利

E.氨氯地平