一、变化规则
1.一般单音节词和少数以-er,-ow结尾的双音节词,比较级在后面加-er；
（1）单音节词
如：small→smaller short→shorter
tall→taller great→greater
（2）双音节词
如：clever→cleverer narrow→narrower
2.以不发音e结尾的单音节词,比较在原级后加-r；
如：large→larger nice→nicer able→abler
3.在重读闭音节（即：辅音＋元音＋辅音）中,先双写末尾的辅音字母,比较级加-er；
如：big→bigger hot→hotter fat→fatter
4.以“辅音字母＋y”结尾的双音节词,把y改为i,比较级加-er；
如：easy→easier heavy→heavier
busy→busier happy→happier
5.其他双音节词和多音节词,比较级在前面加more；
如：beautiful→more beautiful
different→more different
easily→more easily
二、比较级的几种主要句法
1.问人的句法：
陈述句：SuHai is older than SuYang.
一般疑问句：Is Su Hai older than Su Yang?
特殊疑问句：Who is older than SuYang?
选择性的特殊疑问句：Who is older, Su Hai or Su Yang?
2.问物的句法：
陈述句：His ruler is longer than her ruler.
一般疑问句：Is his ruler longer than her ruler?
特殊疑问句：Whose ruler is longer than her ruler?
选择性的特殊疑问句: Whose ruler is longer, his or hers?
