1.
Small smaller the smallest
Tall taller the tallest
Old older the oldest
Old - finished most old - finished the most old - finished
Messy messier the messiest
Light lighter the lighter
Clean cleaner the cleanest
Colourful more colorful the most colourful
Comfortable more comfortable the most comfortable
Large larger the largest
Modern more modern the most modern
Bad worse the worst
Thin thinner the thinnest
Fat fatter the fattest
Good better the best
2.
1 more interesting
2 more modern
3 the most modern
4 the most interesting
5 more beautiful
6 smaller
7 cheaper
8 bigger
9 noiser
10 the oldest
3.
1 This newspaper is more interesting than the book.
2 This house isn't more modern that one.
3 His flat is more comfortable than mine.