To lie or not to lie?

lie vi    ([sb]: not tell truth) --- MENTIR
Note: conjugation: lie - lied - lied
     She lied to her parents about where she was on Friday night.
     Mintió a sus padres sobre donde estaba el viernes por la noche.

lie vi    ([sb]: recline) --- TUMBARSE
Note: conjugation: lie - lay - lain
     If I lie on the sofa, I'll fall asleep.
     Si me echo en el sofá, me quedaré dormido.

lie vi    ([sth]: be spread out) --- EXTENDERSE
     The papers lie all over his desk.
     Los papeles se extienden por todo el escritorio.

lie, be lying vi    (item: be, stay) --- ESTAR
Note: conjugation: lie - lay - lain
     His book lay on the table unread.
     El libro estaba en la estantería de abajo.

And just in case....

Lay vt --- PONER, COLOCAR

It is a regular verb (lay-laid-laid).
It's transitive (takes an object), lay something.

Lie is an irregular verb (lie-lay-lain).
It's intransitive (no object), something lies (down).