DIFFICULT
more difficult
HEAVY
heavier
SLOW
slow-er
NOISY
noisier
WEAK
weak-er
OLD
old-er
EASY
easier
SMALL
smaller
STRONG
strong-er
DANGEROUS
more dangerous
CHEAP
cheaper
HIGH
higher
HAPPY
happier
SLOW
slower
EXPENSIVE
more expensive
DIFFERENT
more different
BEAUTIFUL
more beautiful
BIG
bigg-er
FAT
fatt-er
THIN / SLIM
thinner / slimmer
BAD
worse