制冷剂在系统中的状态是（）。
A、物理性质
B、化学性质
C、物理变化
D、化学变化
参考答案：C
He _____ me. It's a shame my mobile phone was power-off. [ ]
A. ought to have called
B. may be calling
C. might have called
D. would call
桑菊饮与桑杏汤中均含有的药物是（）
A.杏仁
B.桔梗
C.象贝
D.连翘
E.苇根
