-Will you go to the party with us?              

-I'm not sure, I ___ go to visit my grandma with my cousin.              [ ]

A. must            

B. can              

C. have to          

D. may

患者日前泻利日久，且滑脱不禁，有脐腹疼痛，食少神疲，舌淡苔白，脉迟细。治疗应首选的方剂是（）

A.四神丸

B.真人养脏汤

C.六君子汤

D.参苓白术散

E.补中益气汤