--- Is there any possible way to help them get rid of such a bad habit?

--- To tell the truth, it’s very hard. But we   on this problem trying to improve the situation.

A．worked

B．had worked

C．are working

D．had been working

以下哪项不是门静脉高压后形成的侧支 （ ）

A．胃左静脉

B．食道胃底静脉

C．肝圆韧带

D．脾肾静脉

E．静脉韧带