单项选择题
A.0.5m;0.3m B.0.3m;0.3m C.0.5m;0.2m D.0.3m;0.2m
A.不应小于85% B.不应小于75% C.不应小于90% D.不应小于80%
A.0.25m B.0.3m C.0.4m D.0.5m