机械密封是一种依靠弹性元件对静、动环端面密封副的预紧和（）压力与弹性元件压力的压紧而

青黛入丸散剂的用量是（）

A.5～10g

B.0.5～1g

C.1～5g

D.0.25～0.5g

E.1.5～3g

试述侵蚀性葡萄胎和绒毛膜癌时进行化疗常选用的药物。

You can come at any time this afternoon. I'll wait for you ______ 6 o'clock. [ ]

A. until

B. at

C. after

D. from

Who is that beautiful woman?        

-- Mrs Li. She teaches _____ English very well. She always makes her classes______.

A．our;, interesting

B．us; boring

C．us; lively

D．our, surprising

患者误服农药中毒，瞳孔缩小，面肌颤动，呼气中有大蒜样气味选用哪种洗胃液最安全方便：（）

患者误服农药中毒，瞳孔缩小，面肌颤动，呼气中有大蒜样气味选用哪种洗胃液最安全方便：

A.高锰酸钾溶液

B.碳酸氢钠溶液

C.酸性液

D.清水

E.生理盐水