— I telephoned him twice and I couldn’t get through to him. 

—The line might have been out of order, _______?

A．don’t you

B．wasn’t it

C．do you

D．hadn’t it

下腔静脉阻塞时，腹壁静脉曲张的血流方向为（）

A．脐上脐下均向上

B．脐上脐下均向下

C．脐上向上、脐下向下

D．脐上向下、脐下向上

E．以脐为界向上走行