an old man - an older man - the oldest man
a nice pat - a nicer pat - the nicest pat
a funny story - a funnier story - the funniest story
big shops - bigger shops - the biggest shops
a clever dog - a cleverer dog - the cleverest dog
an interesting book - an more interesting book - the most interesting book (тут я не уверена )
a beautiful girl - a more beautiful girl - the most beautiful girl
an exciting match - an more exciting match - the most exciting match
a good son - a better son - the best son
a bad film - a worse film - the worst film
good children - better children - the best children
bad food - worse food - the worst food