“分等级”怎么读？

牛奶分等级出售.The milk is sold in grades.牛奶是分等级出售的.Milk is sold in grades.防尘口罩根据它们的防护效果分等级。Dust masks are graded according to the protection they offer....

“分等级”的英语可以翻译为：graduation，gradation，graduate ...