该类库将包含两个基类宣布为抽象的（它们不能被实例化） ，但我会利用这些基类，用于继承。

The library will contain two base classes declared as abstract (they can't be instantiated), but I will use them as base classes for building application-specific classes through inheritance.

youdao

基类中的私有成员被继承，但不能从派生类访问。

Private members in base classes are inherited but are not accessible from derived classes.

youdao