1) The Sahara is the biggest desert in the world.
It is a most important problem.
=It is a very important problem.
(错) Tom is the tallest of his three brothers.
(对) Tom is the tallest of the three brothers.
2) 下列词可修饰最高级，by far, far, much, mostly, almost
This hat is nearly / almost the biggest.
This is the very best.
This is much the best.
Africa is the second largest continent.
Mike is the most intelligent in his class.
Mike is more intelligent than any other students in his class.
4) "否定词语+比较级"，"否定词语+ so… as"结构表示最高级含义。
Nothing is so easy as this.
=Nothing is easier than this.
=This is the easiest thing.