—I phoned you at 7:00 this morning. But there was no answer.

—Well, maybe I ____________morning exercises at that time. [ ]

A. was doing          

B. did              

C. is doing            

D. would do

单纯性小肠梗阻的X线征象表现为（）

A.假肿瘤征

B.空、回肠换位

C.短小液平面

D.较长液平面

E.连贯、规则、紧靠扩张的肠曲