Use infinitive constructions instead:
1. Tom asked his friend if he could do him a favour. (use 'to want')
2. If Mark wants to travel to America, he should buy some travel brochures. (use 'had better')
3. There is a lot of work that we must finish first.
4. If you need help, Mr Clark is the man who you should ask.
5. The last player that arrived on the playing field was the goalkeeper.
6. Jim Sanders thought that his German pen-pal would visit him.(use 'to expect')
7. If you want to get good grades, you should not disrupt classes all the time. (use 'had better')
8. My father expected that I would apologize for my bad behaviour.
9. The police observed the robber when he broke the window.
10. It was the strangest idea which was ever realized.
11. The next house which will be built will be the townhall.
12. I must remember that I have to give him the money.