foundation
美[faʊnˈdeʃən] 网络基础；地基；基础上；基
1 . She dug the foundation with a pick and shovel.
她用镐和平锹挖地基。
来自柯林斯例句
2 . I am determined to build on this solid foundation .
我决定在这个坚实的基础之上继续努力。
来自柯林斯例句
3 . The Bush Foundation has funded a variety of faculty development programs.
布什基金会已经资助了许多教员发展项目。
来自柯林斯例句
4 . The issue strikes at the very foundation of our community. 这个问题严重影响了我们社会的基本根基。来自柯林斯例句5. The Foundation is holding a dinner in honour of something or other.
基金会正举办某个纪念宴会。
来自柯林斯例句
1.the basis on which something is grounded;
there is little foundation for his objections
2.an institution supported by an endowment
3.the fundamental assumptions from which something is begun or developed or calculated or explained;
the whole argument rested on a basis of conjecture
4.lowest support of a structure;
it was built on a base of solid rock
5.education or instruction in the fundamentals of a field of knowledge;
he lacks the foundation necessary for advanced study
6.a woman's undergarment worn to give shape to the contours of the body
7.the act of starting something for the first time; introducing something new;
she looked forward to her initiation as an adult
Foundation类层次 Foundation类层次的根是NSObject类，它（和NSObject及NSCopying协议一起）定义了基本的对象属性和行为。 Foundation框架的剩余部分由几组相互关联的类和一些独立的类组成。有一些代表基本数据类型的类，如字符串、字节数组、用于存储其它对象的集合类；一些代表系统信息的类，如日期类；还有一些代表系统实体的类，比如端口、线程、和进程。图1、图2、和图3所示的类层次描述了这些类的逻辑分组及其继承关系。 Fo