最易伤肺的病邪是
A.风 B.寒 C.火 D.湿 E.燥
参考答案:E
15. —When Lily fainted, we could have turned to your father for help.
—Yes, sending her to hospital _________ necessary.
A.hadn’t been
B.wasn’t
C.wouldn’t be
D.weren’t
在交流放大器中引入负反馈,可以()。
A.稳定静态工作点
B.放大倍数
C.输出电压
D.稳定静态工作点、放大倍数、输出电压和输出电流