1. He climbed a flight of stairs.
2. She lives two flights up
3. The birds took flight.
4. He was flung into prison.
5. He flung the door open.
6. He flung himself into a chair.
7. The wardrobe was flush with the wall.
8. The blood flushed into his face.
9. He flushed the toilet and washed his hands.
10. You catch more flies with honey than with vinegar.
11. That ship flies the British flag.
12. I am nobody's fool.
13. There's no fool like an old fool.
14. Stop fooling about/around with that gun.
15. He got cold feet.
16. Do you have a foot in both camps?
17. The poor man has one foot in the grave.
18. The boy already stands on his own two feet.
19. You started off on the right foot.
20. He jumped to his feet.
21. It comes into force on 1st January.
22. Well have to yield to force.
23. I'm really looking forward to my holidays.
24. That was very forward of you.
25. He is in a good frame of mind.
26. I didn't like the way he framed the question.
27. He is free with his money.
28. You have a free hand.
29. She was given a free hand in dealing with the situation.
30. We have fresh bread for lunch.
31. We'll make a fresh start.
32. Take a fresh sheet of paper.
33. He put on a bold front.
34. They went off at full speed.
35. Write your name in full.
36. They are making fun of him.
37. They are going to spoil the fun.
38. That's the funny thing about it.
39. Let's have no funny business.
40. That's funny!
Thank you, DuHast.