Attention, please. Sorry to tell you the flight has to be ______because of the heavy snow.

A．put away

B．put up

C．put off

D．put on

贲门失弛缓症的表现有（）

A.吞咽困难症状时轻时重

B.呕吐食管内潴留的食物

C.X线吞钡检查：有食管扩张并有液平面，下端呈鸟嘴状

D.腹部可扪到肿块，压之有水声

E.胸骨后闷胀