宫颈癌临床分期，下列哪项错误（）。

A.癌瘤组织位于宫颈上皮内为癌前期

B.肉眼检查可区分Ⅰa和Ⅰb期

C.癌瘤已侵犯 * * 未达下1/3，无明显宫旁浸润，属Ⅱa

D.癌瘤扩展到宫旁组织已达盆壁，可阻塞输尿管，肾功能不全，为Ⅲ期

E.癌瘤侵犯膀胱粘膜或直肠粘膜者属于Ⅳ期

The clock was striking twelve ______ down the street.

A．because I walked

B．as I walked

C．since I was walking

D．while I was walking