Long
long / longer / the longest
Slow
slow / slower / the slowest
Big
big / bigger / the biggest
Young
young / younger / the youngest
Bad
bad / worse / the worst
Good
good / better / the best
Short
short / shorter / the shortest
Fat
fat / fatter / the fattest
Happy
happy / happier / the happiest
Tall
tall / taller / the tallest
Heavy
heavy / heavier / the heaviest
Small
small / smaller / the smallest
Old
old / older / the oldest
Thin
thin / thinner / the thinnest
Fast
fast / faster / the fastest