1) big- bigger- the biggest.
2) late - later - the latest.
3) good- better- the best.
4) beautiful - more beautiful- the most beautiful.
5) early- earlier- the earliest.
6) ugly - uglier - the ugliest.
7) dirty - dirtier- the dirtiest.
8) young - younger - the youngest.
9) bad - worse- the wosrt.
10) slow - slower- the slowest.
11) sad - sadder - the saddest.
12) rich - richer - the richest.
13) happy - happier - the happiest.
Слова ,у которых много слогов ( типа beautiful) используются со словами "more"( сравнительная степень) , "most"( превосходная).