定痫丸出自于:()
A.《医学心悟》
B.《景岳全书》
C.《丹溪心法》
D.《古今医鉴》
E.《临证指南医案》
参考答案:A
---We thought he would have won the game.
---What a pity! He too nervous when playing.
A.had been
B.has been
C.was
D.would have been
如果某产品市场存在外部正效应,那么可以断定( )。
A.边际社会成本超过边际私人成本
B.边际私人成本超过边际社会成本
C.边际社会收益超过边际私人收益
D.边际私人收益超过边际社会收益