食管癌发病的相关因素包括（）。
A.吸烟
B.饮酒
C.烫食
D.缺乏运动
E.腌制食品
参考答案：A, B, C, E
It was along the Mississippi Rever ____Mark Twain spent much of his childhood.
A．how
B．which
C．that
D．where
简述各种直轴法适用于轴的种类？
