—What were you doing when the UFO arrived?— I         with my dog on the street.

A．walked

B．was walking

C．is walking

D．have walked

胆囊造影检查前1～3天进高脂肪食物准备，目的是（）

A.减轻过敏反应

B.增强病人体质

C.使胆道系统扩张

D.增加胆汁的生成

E.排空胆囊内存留的陈旧胆汁