—Was the driving pleasant when you went to Mexico last summer?

—No, it ________ (rain) for four days when we arrived, so the roads were very muddy.

上消化道出血病因诊断的首选检查方法是（）

A.腹部CT

B.X线钡剂造影检查

C.放射性核素扫描

D.急诊内镜检查

E.腹腔动脉造影