lie and lay

lie: /lai/
*verb (lies; lying; lay/lei/; lain/lein/)
1_(of a person or an animal) to be or put yourself in a flat or horizontal position so that you are not standing or sitting
to lie on your back
the cat was lying by the fire

2_(of things) to be or remain in a flat position on a surface
clothes were lying all over the floor

3_to be, remain, or be kept in a particular state
the machines have lain idle since the factory closed

4_(of a town, natural features, etc) to be located in a particular place
the town lies on the coast

*verb (lies; lying; lied; lied)
to say or write something that you know is not true
you could see from his face that he was lying
don`t lie to me

lay: /lei/
*verb (laid; laid /leid/)
put down; spread
1_to put sb/sth in a particular position, especially when it is done gently or carefully
she laid the baby down gently on the bed
he laid a hand on my arm

2_if a bird, an incect or a fich, etc. lays eggs, it produces them from its body

3_to lay the table: to arrange knives, forks, plates, etc. on a table ready for a meal.

Nota: Estos tres verbos se confunden usualmente, especialmente lie (acostarse) y lay (poner o colocar). Me parece que la diferencia fundamental es:
lie /lay/ (acostarse) es intransitivo -you lie-
lay /lei/ (poner, colocar) es transitivo -you lay something-

*lie (acostarse) es irregular y se pronuncia /lai/
pt lay se pronuncia /lei/
pp lain se pronuncia /lein/

*lay (poner, colocar) es irregular y se pronuncia /lei/
pt laid
pp laid ambos se pronuncian /leid/

*lie (mentir) se pronuncia /lai/ y es regular
pt lied
pp lied

Hay mas signficados de estos verbos pero el objeto de este post es dejar clara la diferencia entre los tres.