What are some common idioms and expressions in English?

Sure, here are some common idioms and expressions in English:

1. Break a leg
2. Bite the bullet
3. Break a sweat
4. Catch a cold
5. Close the deal
6. Come in handy
7. Cut the cord
8. Do it yourself
9. Eat your words
10. For all intents and purposes
11. Go the extra mile
12. Have a ball
13. Keep your chin up
14. Let sleeping dogs lie
15. Make a fool of yourself
16. On the same page
17. Out of the blue
18. Put your foot in your mouth
19. Raining cats and dogs
20. Run a mile and come back for more

These are just a few examples, and there are many more idioms and expressions in English. However, these are some of the most commonly used and understood idioms and expressions.