1) the sahara is the biggest desert in the world.
形容詞最高級前通常必須用定冠詞 the，副詞最高級前可不用。
形容詞most前面沒有the，不表示最高級的含義，只表示"非常"。
it is a most important problem.
=it is a very important problem.
注意： 使用最高級要注意將主語包括在比較範圍內。
(錯) tom is the tallest of his three brothers.
(對) tom is the tallest of the three brothers.
2) 下列詞可修飾最高級，by far, far, much, mostly, almost
this hat is nearly / almost the biggest.
注意：
a. very可修飾最高級，但位置與much不同。
this is the very best.
this is much the best.
b. 序數詞通常只修飾最高級。
africa is the second largest continent.
3) 句型轉換：
mike is the most intelligent in his class.
mike is more intelligent than any other students in his class.
4) "否定詞語+比較級"，"否定詞語+ so… as"結構表示最高級含義。
nothing is so easy as this.