1 形容词最高级前 加the
He is the tallest boy in our class.
2 副词最高级前可以省略
He runs (the ) fastest.
3 越来越.结构 the more.the more 比较级前也加the
The busier he is,the happier he feels
4 两者中较如何的也加the 特指
He is the taller of the two.