Lay and lie are confused all the time, and it doesn't help that the past of "lie" is "lay".
1. Lay → put something down
Lay always has an object (the thing you put down): you lay something.
- Please lay the baby on the bed.
- She laid her keys on the table.
Trick: ask "lay what?". If there is an answer, use lay.
2. Lie → be flat, rest
Lie never has an object.
- I need to lie down. (not "lay down")
- The dog is lying in the sun.
- The town lies at the foot of the mountain.
3. The forms
- lie, lay, lain, lying: Yesterday I lay on the beach. I have lain here for an hour.
- lay, laid, laid, laying: Yesterday I laid my towel on the sand. I have laid the table.
4. Lie → say something untrue
This is another verb, and it is regular: lie, lied, lied, lying.
- He lied to me about the money.
5. Fixed expressions
- lay the table, lay eggs, lay off workers
- lie low (hide for a while), lie in (stay in bed late)
6. Common mistakes
- ❌ I'm going to lay down.
- ✅ I'm going to lie down.
- ❌ Yesterday I laid in bed all morning.
- ✅ Yesterday I lay in bed all morning.
- ❌ The dog is laying by the fire.
- ✅ The dog is lying by the fire.
