'Lie' is an intransitive verb. 'lie' is something you do to yourself
'Lay' is transitive. 'lay' is something you do to something/someone else.
Lie:
You look tired. Lie down and rest.
Lay:
Lay down the keyboard and step away from the computer!
The past tense of 'lie' is 'lay', and the past tense of 'lay' is 'laid'.
He lay in his bed listening to music
She laid the baby in her crib


Comments: 12
I looked it up and only than I understood the difference properly.
Gautami, when will you get to my favorite peeve....
LESS/FEWER.
you are good, and you do well.
One of my pet peeves is till/until. Will touch that next.