原级，比较级，最高级词形变化：
1.（单元音＋单辅音）的单音节词
fatfatterfattest
thinthinnerthinnest
hothotterhottest
bigbiggerbiggest
2.以ｙ结尾的双音节词
easyeasiereasiest
heavyheavierheaviest
prettyprettierprettiest
3.劣级比较
less＋形容词／副词原级＋than
例： she is less beautiful than mary.
4.两者之间用比较级，在比较级前加定冠词，三者以上用最高级
例： he is the taller of the two.?
she is the best player of the three.
5.越越的表达法
例： the days are getting hotter and hotter.
the more you study, the more you learn.
6.修饰比较级的词有：much, by far, even, a little, a great deal
例： she is much better now.
切记不要用比较级来修饰比较级。