数学研究数和空间的抽象对象。

Mathematics is concerned with the abstractions of time and space.

youdao

所谓聚类，就是将物理或抽象对象的集合分成相似的对象类的过程。

Clustering process is a collection of physical or abstract objects into object classes similar to the process.

youdao

这个符合级别严格以抽象对象作为资源的内容，但是支持可扩展类型和资源标识符的概念。

This conformance level deals strictly with abstract objects as the content of resources, but it does support the idea of extensible types and identifiers for resources.

youdao

Now these ideas of classes, object-oriented programming, data abstraction, are about 40 years old, they're not new ideas.

面向对象编程的概念，数据抽象的概念，都是40年前就有的老东西了。

麻省理工公开课 - 计算机科学及编程导论课程节选