工作面基本支护参数有（）。
A.老塘冒落高度
B.支柱下缩量
C.支柱工作阻力
D.支柱钻底量
E.支柱初撑力
参考答案：B, C, D, E
It is good for elderly people to be _________ involved in community service.
A．honestly
B．patiently
C．eagerly
D．actively
减水剂
