单项选择题
A.≥99.995%B.≥99.95%C.≥99.99%D.≥99.9%
A.25〜30minB.20〜35minC.20〜30minD.25〜35min
A.≥99.95%B.≥99.99%C.≥99.9%D.≥99.995%