In ancient times, dogs were mainly _____ helping people hunt (打猎). Now they are more useful-they can

help the blinds, search for the bad eggs,... [ ]

A. bad for

B. used to

C. used for

D. good at

中西药联用的特点是

A．协同增效

B．减低毒副反应

C．减少剂量

D．减少禁忌、扩大适应范围

E．减低成本