IV. 1. This train is the most convenient train.
2. The kitchen is larger than the living room.
3. You're fitter than me.
4. The table is so big as the desk.
5. The skirt is more expensive than the dress.
6. This crossword isn't more difficult than that one. 
7. It's the most romantic story I've ever read.
8. Anna is the tallest girl in her class.

III. 1. The most boring
2. The hottest
3. The most useful
4. The most confident
5. The richest
6. The earliest
7. The most powerful
8. The cleverest/most clever
9. The modernest/ most modern