药物的离解常数用下列哪种符号表示（）
A.pH
B.pK
C.pHa
D.pKa
E.以上都不是
参考答案：D
He waited until it was dark ____ nobody could see him clearly.
A．so that
B．in order to
C．although
D．however
下列哪项作用不属于普鲁卡因的作用（）
A.抗高热
B.局麻
C.止痒
D.抑制单胺氧化酶
E.抗惊厥
