n.[生]总纲；超类
Through the use of inheritance, programmers can reuse the code in the superclass many times. 经过继承的使用，程序设计者能许多次重复使用总纲的码。
However, subclasses are not limited to the state and behaviors provided to them by their superclass. 然而，亚纲没被限制在状态和对他们被他们的总纲提供的行为。
Name subclasses in your hierarchies by prepending on an adjective to the superclass name. 在超类名字前加上内容命名你层次中的子类。
