cheap => cheaper => the cheapest

cold => colder => the coldest

thin => thinner => the thinnest 

good => better => the best

fast => faster => the fastest 

colorful => more colorful => most colorful

big => bigger => biggest

expensive => more expensive => most expensive 

popular => more popular => most popular

long => longer => the longest

far => farther => the fasthest 

old => older => the oldest

nicely => more nicely => most nicely

well => better => the best

slowly => more slowly => most slowly

quick => quicker => quickest

bad => worse => the worst

badly => more badly => most badly

modern => more modern => most modern

pretty => prettier => the pretiest

Adj /adv => So sánh hơn => So sánh hơn nhất