◆ The money spent by her parents is less than THAT spent by her children.
上面的例子中that spent by her children 意思是the money spent by her children，也就是说这两部分钱是不一样的，一部分钱是由父母花另一部分由小孩花。所以在使用it 和they 时，其所指代的东西是同样的：
◆ The money spent by her parents is more than IT was expected to be.
而that 和those 时必须对其所说明的词进行修饰以示区分。
◆ The money spent by her parents is less than THAT SPENT by her children.
◆ Her company is outperforming THAT OF her competitor.
◆ Wrong: Her company is outperforming THOSE OF her competitors.
◆ Right: Her company is outperforming THE COMPANIES OF her competitors.
最后，GMAT考试中使用it, they,或 them而不使用this、these、that 或者 those来替换名词，除非修饰that或those：
◆ Wrong: Her products are unusual; many consider THESE unique.
◆ Right: Her products are unusual; many consider THEM unique.