接触性皮炎与急性湿疹的鉴别哪项错误（）
A.皮疹是否境界清楚
B.皮疹是对称发生
C.皮疹是否单一形态
D.皮疹是否瘙痒
E.病因是否明确
参考答案：B
They promised to develop a software package by the end of this year, ________ they might have.
A．however difficult
B．how difficult
C．whatever difficulty
D．what difficulty
肝硬化常见的死亡原因是（）
A.上消化道出血
B.肝性脑病
C.肝癌破裂
D.感染
E.肝肾综合征
