根据成因分，湖泊可分为（）。
A.构造湖
B.火山口湖
C.内陷湖
D.冰川湖
E.泻湖
参考答案：A, B, D
属于法定职业病的是（）
A.建筑工人的腰背痛
B.高空坠物致工人脚外伤
C.收割水稻致农民手外伤
D.纺织工人的噪声性耳聋
E.搬运工人的脚胼胝
—She was in class on Friday afternoon, but no one has seen her since.—She ______ an accident.
A. might have B. might have had C. may have D. ought to have had
