新生儿急腹症多属先天性消化道畸形,常见的有
A.肛门闭锁直肠前庭瘘
B.胃壁肌层发育不良胃破裂
C.先天肥厚性幽门狭窄
D.先天性肠旋转不良回肠扭转
E.肠闭锁
参考答案:B,D,E
—________ have you watched TV tonight?
—For two hours. [ ]
A. How long
B. How much
C. How many
D. How often
有一半径为4m的半球形水池里有2m深的水,现需将水全部抽到距地面6m高的水箱内.
求抽水至少需要做多少功。