下列哪项不属于六淫的致病特点（）
A.季节性
B.环境性
C.传染性
D.外感性
E.转化性
参考答案：C
We ____ there when it ____ to rain. [ ]
A. were getting-would begin
B. were about to get-began
C. had got-had begun
D. would get-began
食管癌的典型临床症状是（）
A.吞咽疼痛
B.食管内异物感
C.胸骨后烧灼感
D.进行性吞咽困难
E.呕吐黏液
