下列哪种局麻药只能用于表面麻醉（）
A.利多卡因
B.丁卡因
C.可卡因
D.达克罗宁
E.布比卡因
参考答案：D
He waited ________ the volcano became quiet and he was able to return two days later.
A．when
B．before
C．as
D．until
下列哪项不是颅脑增强扫描的目的（）
A.区分梗死与水肿
B.观察肿瘤的血运情况
C.明确肿瘤边界
D.鉴别脑内外肿瘤
E.观察血脑屏障的破坏
