心脏危险指数中，预示麻醉危险性最大（）。

A.非窦性心率，有房早

B.年龄大于70岁

C.急诊手术

D.第三心音奔马律和颈静脉怒张

E.6个月内心内膜下心肌梗死

Useful drugs are made from inorganic substances or are plant and animal by-products.

A．materials

B．derivatives

C．chemicals

D．ingredients