食管癌中晚期的典型症状（）
A.胸骨后烧灼感
B.食管内异物感
C.咽下食物哽噎感
D.咽下食物停滞感
E.进行性咽下困难
参考答案：E
Paper money was in ____ use in China when Marco Polo visited the country in ____ thirteenth century.
A．the; /
B．the; the
C．/; the
D．/; /
简述钻机探水安全注意事项。
