Walmart, which is one of the largest American supermarket chains,         some of its store open 24 hours on Mondays through Saturdays.

A．keeps

B．keep

C．have kept

D．had kept

良性胃溃疡患者，龛影周围表现中（）

A.粘膜水肿

B.粘膜纠集

C.肿块

D.粘膜中断

E.器官变形