That is, you must access them using an object instance, via the$ this pseudo-variable or an object reference stored in a standard variable. 也就是说,必须使用对象实例,通过$this伪变量或标准变量中存储的对象引用来访问方法和属性。
The$ this pseudo-variable provides a mechanism for objects to refer to their own properties and methods. $this伪变量提供了一种用于对象引用自己的属性和方法的机制。