合理用药安全性的实质内容是
A．药物的毒副作用最小
B．无不良反应
C．风险/效应尽可能小
D．无致畸形
E．无致癌性
参考答案：C
果园去年采摘水果a千克，今年比去年采摘水果的2倍还多b千克，今年采摘水果（ ）千克．
A．2a+b
B．2a-b
C．2（a+b）
D．2（a-b）
Nobody believed his reason for being absent from class__________he had to meet his uncle at the airport.
A．why
B．that
C．where
D．because
