试管婴儿一般于卵子受精后何时移植到宫腔()
A．4～8个细胞
B．8～16个细胞
C．32个细胞
D．64个细胞
E．128个细胞
参考答案：B
志贺氏菌属依抗原结构分为A群痢疾志贺氏菌，B群福氏志贺氏菌，C群（），D群宋内志贺氏菌。
Some historians believe that John Jay could have played （） in America's history as James Madison.
A．as an important role
B．as important a role
C．an important role as
D．a role as important
