ig,bigger,biggest
small,smaller,smallest.
long,longer,longest,
short,shorter,shortest,
fat,fatter,fattest.
thin,thinner,thinnest.
good,better,best,
well,better,best.
bad,worse,worst,
far,farther,farthest,
old,older,oldest.
happy,happier,happiest,
great,greater,greatest,
cold,colder,coldest,
much,more,most,
hot,hotter,hottest
hard,harder,hardest.
clever,cleverer,cleverest
narrow,narrower,narrowest
很多的,找到其中的规律就行了