clean
cleaner - the cleanest
cheap
cheaper - the cheapest
bad
worse - the worst
happy
happier - the happiest
big
bigger - the biggest
dirty
dirtier - the dirtiest
clever
cleverer - the cleverest
shy
shyer - the shyest
pretty
prettier - the prettiest
good
better - the best
new
newer - the newest
little
less - the least
difficult
more difficult - the most difficult
narrow
narrower - the narrowest
many
more - the most
high
higher - the highest