慢性肝炎的病程一般超过（）
A.2周
B.1个月
C.2个月
D.4个月
E.6个月
参考答案：E
Last night, there was a food accident. The _______ were ill, but no _______ were lost.
A．child, lives
B．children, life
C．children, lives
D．child, life
简述社区研究的主要意义。
