便血伴腹部包块者见于（）
A.结肠癌
B.肠结核
C.肠道恶性淋巴瘤
D.Crohn病
E.肠套叠
参考答案：A, B, C, D, E
社会历史是自然历史的过程。( )
His father was really a ____ person. Once he made up his mind, nothing could change it. [ ]
A. familiar
B. brave
C. clever
D. stubborn
