1. It's as light as a feather. 2. It's as dry as a bone. 3. It's as flat as a pancake. 4. He's as mad as a hornet. 5. It's as old as the hills. 6. It's as quick as lightning. 7. She's as sick as a dog. 8. He's as strong as an ox. 9. They're as different as night and day. 10. She's as stubborn as a mule. 11. He's as proud as a peacock. 12. She's as white as a sheet. (usually used when someone is very afraid or very sick) 13. It's as solid as a rock. 14. It's as good as new. (used after something broken has been repaired) 15. It's as clear as mud. (= it's not clear at all)