白居易生活和创作的社会背景是( )
A．经历了唐由盛而衰的变迁
B．遭遇安史之乱的颠沛流离
C．逢藩镇割据战乱
D．受唐末农民战争冲击
参考答案：C
学龄前儿童尿量每日少于多少称为少尿
A．400ml
B．300ml
C．200ml
D．100ml
E．80ml
No one told us . We need your help. [ ]
A. how to do it
B.what to do it
C. how should we do
D. what should we do
