11 Most Common Grammar Mistakes Employees Make (Kathy& Ross Petras at KandRPetras.com)

Lay's most common meaning is "to place (something or someone) down in a flat position.”

Lie's corresponding meaning is "to be in a flat position on a surface."

Here's lay:

I was told to lay the book down.

I laid it down as I have laid other books down.

I am laying more books down now.

And here's lie:

I was told to lie down.

I lay down.

I have lain here since.

I'm still lying here.