你可以导航到使用，声明，继承，基类和更多—交叉语言。

You can navigate to usages, declarations, inheritors, base types and more - across languages.

youdao

到这里为止，我们学习了如何声明一个类，如何初始化它们，以及继承的一些基础。

So far, we've covered how to declare classes, how to instantiate them, and some of the basics of inheritance.

youdao

继承抽象类的子类必须实现在其父类或自身中声明为抽象的所有抽象方法。

A child class that extends an abstract class must implement all abstract methods in its parent or itself be declared abstract.

youdao