赤石脂的主治病证是
A．久泻不止B．肺虚久咳C．两者均是D．两者均非
参考答案：A
--- I need to advertise for a roommate for next term.
--- __________? Mary is interested.
A．So what
B．What for
C．How come
D．Why bother
简述PIN型的光电二极管的工作原理？
