浮动汇率制度
参考答案：
是指一国中央银行不规定本国货币与他国货币的官方汇率，听任汇率由外汇市场的供求关系自发地决定。
More and more people have come to realize that if we had taken effective measures much earlier, the air quality ______ so seriously now.
A．is not polluted
B．would not be polluted
C．had not been polluted
D．would not have been polluted
石斛夜光丸除了可以清肝明目外，还可以（）。
A.滋肾养肝
B.补脾益肾
C.健脾益气
D.补血养肝
E.滋阴补肾
