Answer:
16. The court's verdict sets a precedent for future cases.
17. A good teacher is the one who instills confidence in one's story.
19. Diabetic patients can run a normal life providing they keep to their prescribed regimen.
20. Delegates will be invited to consent unilateral nuclear disarmament, otherwise they will suffer serious consequences.
21. A ticket is only valid for 1 hour after its being issued.
I am not sure about the number 15 and 18 that's why it's not included in my answer. I hope it helps you, even just a bit :)