用显微镜观察小鱼尾鳍内血液流动时，辨别毛细血管的典型特征是_____________________。
只允许红细胞呈单行通过
下列关于非营利组织成立的论述中，正确的有( )。
A．首要目的不是营利
B．目的是提高社会福利
C．促进政治和社会变革
D．提高企业的上缴利润
It was not until Mum agreed to take her to KFC, ____was her favorite, ____the girl stopped crying. [ ]
A. that; that
B. which; which
C. that; which
D. which; that
