Ответ:

1. My brother is very tall, but my father is taller (tall) in our family.
2. For me, kindness is more important than a good sense of humour.
3. She is the most intelligent student in our class.
4. This new student is much shyer than the others.
5. Who is the best football player in the world?
6. Her hair is longer than her sister's.
7. This is the worst day of my life!
8. Could you give me less sugar in my tea, please? I'm on a diet.
9. His new car is better than his old one, but it's not the best car on the market.
10. We need to have much more information before we decide.
11. Of all the paintings in the gallery, this one is the most beautiful.
12. She is slimmer than her sister.
13. Your plan is more sensible than mine.
14. It was a farther journey than we had expected.
15. He is the most impatient person I have ever met.