Положительная

small

The elephant is small.

Сравнительная

smaller

The mouse is smaller than the elephant.

Превосходная

the smallest

The ant is the smallest of these animals.

Попробуйте сами:

Положительная Сравнительная Превосходная
good better the best
bad worse the worst
many/much more the most
little less the least
far farther/further the farthest/furthest