关于食管内支架置入术的适应证，下述正确的是（）
A.食管癌狭窄
B.食管结核
C.完全梗阻
D.弥漫性狭窄
E.食管平滑肌瘤
参考答案：A
After six years of married childlessness, the husband was suddenly ________ by his wife ________
a boy and a girl. [ ]
A. presented; with
B. present; to
C. given; with
D. given; to
碳钢锅炉管厚4mm，在无水垢和积灰的情况下，如果内壁温度为175℃，外壁温度为181℃，试问每小时每平方米的受热面传递了多少热量？（碳钢导热系数λ=39大卡/米·时·℃）
