I, 1.B 2.C 3.A II, Fast- the fastest, big- the biggest, short- the shortest, better- best, noisier- the noisiest?, longer- the longest, smaller- the smallest, happier- happiest, older- oldest, harder- hardest, younger- youngest IV, 1 Hoa is shorter than Lan 2 my sister is smaller than i am 3 i cook is worse than jane 4 my dad is older than my mom 5 minh is fatter than nam III, 1 bigger 2 longer 3 highest 4 shortest 5 older 6 deepest 7 hottest 8 shorter 9 younger 10 smaller 11 taller 12 thicker 13 longest 14 higher 15 happiest 16 best 17 thinnest 18 coldest