子宫颈癌好发部位是
A．子宫颈管B．子宫颈内口C．子宫颈外口D．子宫颈前唇E．子宫颈后唇
参考答案：C
Last Saturday, we were walking along the street _____ a car suddenly knocked an old man over.
A when B while C as D since
所有的主飞行控制都由液压作动器PCA驱动，副翼系统有几个PCA？（）
A、3个
B、6个
C、8个
D、12个
