单项选择题
A.70% B.80% C.90% D.100%
A.70%B.80%C.90%D.100%
A.50% B.60% C.70% D.80%
A.30% B.35% C.40% D.45%
A.40% B.50% C.60% D.70%
A.35% B.45% C.55% D.65%