keystone ['ki:stəun]以下由轻松背单词网站提供
单词级别附加级基本释义n.拱顶石,基础参考例句Social justice is the keystone of their political program. 社会公平是他们政治纲领的基本原则。Quantitative measurements of one sort or another serve as the keystone of engineering practice. 定量测定一种或多种成分是环境工程中的重要项目。 推荐阅读 |