凝胶过滤层析分离物质的基础是利用()
A.各组分分子的大小不同
B.各组分溶解度的不同
C.各组分带电荷的不同
D.各组分沉降率的不同
E.各组分密度的不同
— I'm surprised to hear that Sue and Paul have _____.
— So am I.They seemed very happy together when I last saw them. [ ]
A. closed up
B. finished up
C. divided up
D. broken up