病人有脓血便及肛门下坠感1月,应先作
A.乙状结肠镜检查
B.粪便培养加药物敏感试验
C.X线钡剂灌肠检查
D.纤维结肠镜检查
E.直肠指检
参考答案:E
在严寒的冬季,滑雪场的人工造雪机在工作时不断将水吸入,并持续从造雪机的前方喷出“白雾”,而在“白雾”下方,已经积了厚厚的一层“白雪”。对于造雪机在造雪过程中,水这种物质发生的最主要的物态变化,下列说法中正确的是( )
A.凝固
B.凝华
C.升华
D.液化
Which of the following is true
A.Male insects are always smaller than females.
B.In a given species nature provides differences between sexes to secure successful production.
C.Size and strength protect females from other females.
D.Longevity is characteristic of the Dynastes and Megasoma.