If you need to identify a special sort of class or add metalevel information to a class, then you must use UML extensions.

如果需要标识特定类型的类或者增加类的元数据层信息，就必须使用UML扩展。

youdao

Love is many not work out all the time but it leaves you a special sort of feeling, like nothing you have ever imagined.

它也许不是每次都很美好，但它都会给你留下一点特殊的感觉，一种你以前从来没有过的感觉。

youdao

Love is many not work out all the time but it leaves you a special sort of feeling, like nothing you have ever imagined.

它也许不是每次都很美好，但它都会给你留下一点特殊的感觉，一种你以前从来没有过的感觉。

youdao