I can’t leave the office now. A lot of work ________ to be done.

A．is remained

B．left

C．remains

D．have

治疗经行泄泻肾虚证，应首选（）

A．补中益气汤

B．香砂六君子汤

C．人参养营汤

D．参苓白术散

E．健固汤合四神丸