1、inherited 就是执行父类的同名方法，所以有区别，就是说是先执行父类同名方法还是直接自己写的代码
2、正在学习中，鸟语看不懂
A class-reference type, sometimes called a metaclass, is denoted by a construction of the form
class of type
where type is any class type. The identifier type itself denotes a value whose type is class of type. If type1 is an ancestor of type2, then class of type2 is assignment-compatible with class of type1. Thus
type TClass = class of TObject;
var AnyObj: TClass;
declares a variable called AnyObj that can hold a reference to any class. (The definition of a class-reference type cannot occur directly in a variable declaration or parameter list.) You can assign the value nil to a variable of any class-reference type.
To see how class-reference types are used, look at the declaration of the constructor for TCollection (in the Classes unit):
type TCollectionItemClass = class of TCollectionItem;
...
constructor Create(ItemClass: TCollectionItemClass);
This declaration says that to create a TCollection instance object, you must pass to the constructor the name of a class descending from TCollectionItem.
Class-reference types are useful when you want to invoke a class method or virtual constructor on a class or object whose actual type is unknown at compile time.
