A: Do you know _______ for advice when we have problems.

B: You can talk to your parents or teachers. [ ]

A. who to talk

B. when to talk to

C. who to talk to

D. who can we talk to

临床资料证明对胎儿有危害，但孕妇用药有效又缺少替代药物称为

A．A类
B．B类
C．C类
D．D类
E．X类