5) не знаю.
6) thin - thiner - thinest
difficult - difficulter or more difficult - difficultest or most difficult
bad - wors - worst
nice - nicer - nicest
boring - more boring - most boring
good - better - best
7) 2. most intelligent
3. most expensive
4. younger
5. most beautiful
6. shorter
7. more crowded
8. oldest
9. earlier
10. most famous