急性胰腺炎最常见的原因是
A．梗阻因素
B．酒精中毒
C．暴饮暴食
D．感染
E．外伤
参考答案：A
Yesterday a reporter asked 10 students at Hilltop School _________ last weekend. [ ]
A. what did they do
B. what were they doing
C. what they did
6年前以10万元购入某设备，累计折旧5万元，现在出售该设备可得3万元，则该设备的沉没成本为（）万元。
A．10
B．5
C．3
D．2
