当CO2，ad＜2（％）时，Oad=（）。
参考答案：100一Cad-Had-Nad-Mad-Aad
He has nothing to do today, _____?
[ ]
A. doesn't he
B. do he
C. does he
D. isn't he
阴病治阳适用于( )
A．实寒证B．实热证C．虚寒证D．虚热证
