形容词、副词的比较级和最高级的构成和用法。
（一）比较级和最高级的构成：
1 加-er,-est构成比较级和最高级。
【1】单音节形容词和副词
high-higher-highest hard-harder-hardest
【2】以不发音的-e结尾的
safe-safer-safest late-later-latest
【3】辅音字母要双写的情况：
big-bigger-biggest hot-hotter-hottest
【4】以辅音加-y结尾的情况
dry-drier-driest merry-merrier-merrist
2 加more,most构成比较级和最高级。
【1】多音节的形容词和副词
expensive-more expensive-most expensive
carefully-more carefully-most carefully
【2】由形容词加-ly构成的副词
slowly-more slowly-most slowly
highly-more highly-most highly
【3】以-ful,-less,-able,-ous,-ive,-ing等结尾的双音节形容词
useless-more useless-most useless
serious-more serious-most seriuos
【4】分词形容词tired,pleased及glad,often,real,right,wrong等单音节形容词
tired-more tired-most tired
glad-more glad-most glad
（3）形容词、副词的比较级和最高级的不规则构成法。
good/well-better-best
bad/ill/badly-worse-worst
many/much-more-most
little-less-least
far-farther/further-farthest/furthest
old-older/elder-oldest/eldest
（二）比较级和最高级的用法
1 比较级的表示法：主语+be +比较级+than…;主语+谓语+比较级+than…
（1）不同主语的比较：
He is two years younger than I.
This machine works better than that one.
Li Ming studies harder than Wang Ling.
（2）同一主语不同方面的比较：
She is now happier than she has ever been.
The exam was easier than we expected.
We have had much more rain this year than last year.
（3）用于修饰比较级的词：even,(very) much,far,a lot,still
This book is much thicker than that one.
He works even harder than before.
2最高级的用法以及most/mostly/almost/at most 的含义
（1）形容词和副词最高级的用法
三者或三者以上的比较用最高级。表示最高程度时，用“the+最高级”的结构表示。最高级中表示比较范围的常用among,in,of引导的介词短语或从句表示。
Yesterday was the hottest day of the year.
He works (the) hardest in his class.
Shanghai is among the largest cities in the world.
This is the tallest building in our school.
Of all the books,this is the most useful one for us students.
It is the biggest zoo I’ve ever visited.
（2）修饰最高级的词
最高级可以用序数词以及much,by far,nearly,almost修饰
The Yellow River is the second longest in China.
Of the three boys Jack is almost the cleverest.
（3）可以不加冠词的情况
作状语的副词最高级前可以不加定冠词
Of all the boys he came (the) earliest.
I like spring best.
（4）most,mostly,almost,at most的用法
A most作副词，构成形容词和副词的最高级
most 作副词，构成大多数双音节或多音节形容词和副词的最高级形式，前面常有定冠词。
Which do you think is the most comfortable hotel in this town?
B most 作副词，修饰形容词和副词，用来加强语气，表示“极”“十分”，前面不用定冠词。
It’s most dangerous to play with fire.
C most 作形容词修饰名词。
most 作形容词，意为“大多数的，大部分的，几乎全部的”，修饰名词，前面不用冠词。与most of 同义，但most of 名词前必须加冠词。
Most English words are not difficult to remember.
Most of the students had left when she came.
D mostly意为主要地，多半地，相当于mainly.
He uses his bike mostly for going to school.
The students are mostly young people between the ages of sixteen and twenty.
E almost 意为几乎，相当于very nearly.
He spent almost the whole day reading English.
F at most 意为最多，与at least相对。
I can pay only twenty dollars at most.
1）同级比较中有两种情况：
# 表示双方情况"一模一样"，用as + 原级+ as的结构；
# 表示双方情况"不（那么）一样"，用not so / as + 原级+ as的结构。在这两种结构中，第一个as是副词，而第二个as是连词；在第二个as的后面接名词、句子或代词的主格（一般不要接代词的宾格）。例如：
My parcel is as heavy as yours . 我的包裹与他的一样沉。
Arther calculates as accurately as a calculator.阿瑟象计算器一样计算精确。
His bedroom is not as neat as his sister's. 他的寝室没有他姐姐的整洁。
It is not so hot as yesterday. 今天不象昨天那么热。
I can't speak English as fast as a native speaker. 我说英文没有以英语为母语的人说得快。
2）另外，在as …as 的结构中，第一个as的前面可以加上表示倍数的词、或是某些副词修饰语：twice , ( three ) times , nearly , almost , just , exactly , not nearly（根本不）, by no means（绝不）, quite 等等。例如：
Asia is four tomes as large as Europe. 亚洲有欧洲的四倍大（亚洲比欧洲大三倍）。
James is not nearly as tall as Robert. 詹姆斯根本没有罗伯特高。
Cast iron is almost as useful as steel. 铸铁差不多与钢一样有作用。
