A.20 B.25 C.30 D.35
A.一级品,二级品 B.优等品,一级品 C.优等品,合格品 D.一级品,合格品
A.20% B.25% C.30% D.35%
A.6 B.8 C.4 D.10
A.25mm B.50mm C.22mm D.33mm