III. 最高级用法: 1. 形容词最高级用于in, of 或among的结构中, 形容词最高级前+the eg I am the best of (among)the three. He is the thinnest boy in my class. 2. 副词最高级不需+the eg. Jim goes to bed latest in my family.)
形容词比较级和最高级的 构词规则
一、规则变化
1.单音节和少数双音节单词，一般在词
尾加“er”或“est”。 clean, tall, small, cheap , short, long, light, high 2. 以不发音字母“e”结尾的单词，直接 在词尾加 “r”或“st”。 nice, late, close, fine, large, free, rude
3.4.Biblioteka 以重读闭音节结尾的单词，如果词尾只有一个 辅音字母时，应先双写这一辅音字母，再加 “er”或“est”。 fat, big, red, thin, hot, fat, sad, wet 以辅音字母+y结尾的单词，应先改“y”为“i”， 在加“er”或“est”。 happy , easy, heavy, healthy, busy, lucky, pretty, sunny, funny
II. 比较级用法: 1. 比较级+than 2. 比较级+and+比较级, 表示“越来越”
eg. warmer and warmer, nicer and nicer,
more and more beautiful, more and more fun • the+比较级… the+ 比较级
eg. The more you read the book, the more interesting you found . *** 4. 比较级的修饰语有 : much, far, even, a little, a lot, a bit, rather, still, a great deal (大量) + adj./adv. 比较级 5. 当比较级后没有than, 而为of the two的结构,比较级前加the. eg. The taller of the two girls is Mary.
2. 比较级和最高级互换(比较时要把自己排除在外。注意比较的范围)
eg. Shanghai is the largest city in China.
city Shanghai is larger than any other (单数)city in China.
Shanghai is larger than any city in Africa. eg: John is the thinnest student in the class. John is thinner than any other student in the class. John is thinner than anyone/anybody else in the class.

thanks
5、 其他双音节单词和多音节单词，都在其前面加 “more”或“most”。(beautiful, interesting)
二、 不规则变化。 合二为一共三对:“坏bad”,“病ill”的比较级 为worse,最高级为worst.两多 many/much”的比较级为more,最高级为 most.“两好good/well” 的比较级为better, 最高级为best. 一分为二只两个，一是“远far”的比较级 为farther/further,最高级为 farthest/furthest.二是“老old”的比较级 为 older/elder，最高级为oldest/eldest. 还有一词little“少”的比较级为less,最高 级为least.
I. 原级用法:
*** 1. as+adj/ adv.的原级+ as (肯,否) , (not)so…as (否) eg. The ruler is as long as that one. He sings as well as Jack. He doesn’t sing as(so) well as Jack. 2. as much as, as many as 与…一样多 eg. I have done as much work as he did yesterday. You can take as many books as you can.