限定词包括泛指限定词和特定限定词等只能修饰名词，
然而不定代词不光作定语修饰名词，还可以被介词宾语修饰并作主语和宾语，如both of them are friends和I wish all of you to make progress等。同时不定代词也可作同位语和表语如They both swim well 和Is that all you want to say.
指示代词不光作定语修饰名词，还可以作主语，宾语 ，表语如This is an apple和I like this and he likes that和what I want to say is this
指示代词 :this that these those，所谓代词，就是能指代名词做主语宾语 this is a book 指示限定词：the，相当于形容词，只能起修饰限定作用，不能指代名词。 the book is mine.
