12. It's time for you (finished / to finish) your assignments.
→ to finish

13. It's important that Jane (should take / took) her medicine twice a day.
→ should take

14. I can't concentrate with all the noise you are making. I wish you (keep / would keep) it down for a while!
→ would keep

15. Linda wishes she (can spend / could spend) more time doing the things she likes.
→ could spend

16. You are a liar. I'd rather (never see / didn't see) you again!
→ never see

17. I'd prefer (not to go / didn't go) to the mountain!
→ not to go

18. It's about time for us (to get / get) ready. The guests are coming soon.
→ to get

19. I'd rather (to spend / spend) the whole holiday in my room than (go / went) to the beach with Mark.
→ spend, go

20. I'd prefer (going / to go) to the cinema rather than (having / have) dinner tonight.
→ to go, have

21. It's about time our company (to find / found) a qualified accountant.
→ found

22. It is a good idea that he makes an effort (to learn / learning) how to cope with your troubles.
→ to learn

23. If only my kids (don't make / wouldn't make) too much mess. I'm tired of tidying up my house.
→ wouldn't make