Certainly! Here are the rewritten sentences:

3. The black dress costs more than the white dress.
4. English is easier than Math.
5. Math is more difficult than English.
6. No one in my group is smarter than Mary.
7. Mary is the most intelligent member of my group.
8. No river in the world is longer than the Nile.
9. The Nile is the longest river in the world.
10. Mount Everest is the tallest mountain globally.
11. No mountain is taller than Mount Everest.
12. This computer is superior to that one.
13. That computer is less advanced than this one.
14. The apartment is spacious. The rent is high.
15. The bigger the apartment, the higher the rent.
16. We will leave soon. We will arrive shortly.
17. The sooner we leave, the sooner we will arrive.
18. The joke is amusing. The laughter is loud.
19. The better the joke, the louder the laughter.
20. She feels tired. She is gaining weight.
21. The fatter she gets, the more tired she feels.
22. As he ages, he wants to travel more.
23. The older he gets, the more he wants to travel.
24. The children are excited about the challenging games.
25. The more difficult the games are, the more excited the children become.
26. People drive quickly. Many accidents occur.
27. The faster people drive, the more accidents happen.
28. I dislike him. I feel strongly about it.
29. The more I dislike him, the more it affects me.
30. My boss is busy when he is under pressure.
31. The more time my boss has, the better his performance.
32. He has a lot of money and wants to spend it.
33. The more money he has, the more he wants to spend.

Feel free to adjust any part if needed!