clean-cleaner
wet-wetter
slow-slower
cold-colder
easy-easier
cold-colder
tall-taller
dirty-dirtier
nice-nicer
young-younger
expensive-more expensiver
hot-hotter
ugly-uglier
red-redder
big-bigger
late-later
quick-quicker
good-better
fat-fatter
old-older
beautiful-more beautiful
thin-thinner
happy-happier
loud-louder
bad-worse