one指代上文提到过的同类事物中的一个，但不是上文提到的那一个事物，即“同类不同物”。it代替上文提到的东西。this一般指较近的事物，不能代替前面的东西。that在进行比较时，代替不可数名词，指示代词时，一般指较远的事物。
this造句
1、This stopper belongs to this bottle.
2、This is what this conflict is about.
3、This sounds great, but is this legal?
4、Bustthisbastard's teeth.
5、This will be published later this year.
that造句
1、Does that mean that motivation is unimportant?
2、I know that feeling.
3、True that, Woody.
4、Why not embrace that?
5、We like that answer?