比较级more前面为什么还要加一个the

这里the 是副词，用于比较级或最高级前，表示“那一个”（较好的那个或最好的那个）。跟of 连用，表示比较的范围。对比：

He is the taller of the two brothers.

Of the two brothers, he is the taller.

He is the tallest of the three brothers,

Of the three brothers, he is the tallest.

Tom behaves the more politely of the two boys.

Of the two boys,Tom behaves the more politely.

Tom behaves the most politely of the three boys.

Of the three boys,Tom behaves the most politely.