有关副反应的正确认识是：

A．与药物的选择性高低无关

B．多数难以预料

C．一般反应轻，但较难恢复

D．与药物的药理作用无关

E．治疗量下出现的可逆性不适反应

—Tom graduated from college at a very young age.

—Oh, he ______ have been a very smart boy then.[ ]

A. should

B. can

C. must

D. will