单项选择题
A.1:3~1:5 B.1:8~1:10 C.1:18~1:20 D.1:28~1:30 E.1:45~1:55
A.43~45 B.50—53 C.58~60 D.65--68 E.70~72
A.20%~30% B.35%~50% C.50%~65% D.65%~75% E.75%~85%