2.
1) Peggy's backpack is lighter than mine.
2) The weather today is worse than (it was) yesterday.
3) This house is smaller than that one.
4) This picture is more expensive / cheaper than that one.
5) The Black Sea is colder than the Red Sea.
6) This cauldron is cleaner than that one.
3.
1) It is not as difficult as Exercise 2.
2) The film was not as good as the book. I don't recommend it.
3) My friend's cat is as funny as mine.
4) My new shoes are not as comfortable as my old ones.
5) I'm afraid I can't help you. My backpack is as heavy as yours.