A.3M級B.3D級C.3N級D.3F級
A.鈦的質(zhì)量分?jǐn)?shù)不小于99.99%B.鈦的質(zhì)量分?jǐn)?shù)不小于99.9%C.鈦的質(zhì)量分?jǐn)?shù)不小于99.8%D.鈦的質(zhì)量分?jǐn)?shù)不小于99%
A.90B.100C.110D.120