1.一般情况下直接加er。如:short→shorter
2.以字母e结尾的形容词和副词加r。如:nice→nicer
3.以辅音字母y结尾的Y改为I加er。如:happy→happier
4.重读闭音节结尾的双写结尾辅音字母加er。如:fat→fatter→fattest
5.特殊变化：
good/well→better;
many/much→more;
ill/bad(badly)→worse;
little→less;
old(eld)→older/elder;
far→farther/further
6.多音节词:比较级在形容词.副词前面加more.
如:beautiful→more beautiful
