什么是颜色分阶？
分阶读本是很棒的选择，因为它们专为语言学习者设计。
One excellent source of foreign language exposure is through graded readers, which are designed specifically for language learners.
全自动温度设置程序引导用户分阶程序，以更容易得获得沥青分阶。
A fully automatic temperature setting routine guides the user through the grading process, making asphalt grading as easy as possible.
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