选择适当的选项填在对话的空白处，使其意思完整正确。A. At Home.B.

针对配基的生物学特性的蛋白质分离方法是( )。

A．凝胶过滤
B．离子交换层析
C．亲和层析

（）使中国大革命受到严重的摧残，标志着大革命的部分失败，是大革命从胜利走向失败的重大转折点。

A、四一二反革命 * *

B、马日事变

C、七一五国民党中央“分共”会议

D、“中山舰”事件

血肿位于硬脑膜与脑皮质之间的是（）。

A.脑挫伤

B.脑裂伤

C.硬膜外血肿

D.硬膜下血肿

E.脑内血肿

出血时间延长可见于_____、_____、_____、_____。

A．The widespread use of illegal drugs is the greatest concern of the Americans.

B．Almost all drugs are sold in the poorest neighborhoods in the country.

C．Most Americans agree that they have won a major victory in the drug war.

D．The lengthy debate over legalizing drugs has been recently resolved.