Submitted by Santo J. Aurelio, Ed.D.

The LIE/LAY conundrum is one of the worst grammar problems. Very few speakers and writers use this pair correctly.

To LIE is an infinitive meaning: to RECLINE. Its four forms are: lie (present);
lay (past); has, have, or had lain (participle); and lying (gerund). Examples of usage are:

I'd like to lie down now. (present)
Yesterday I lay down for three hours. (past)
For the last two weeks I have lain down for one hour daily. (participle)
Lying around can be quite wasteful. (gerund)

To LAY is an infinitive meaning: to SET or PUT DOWN, and also to PRODUCE AND DEPOSIT EGGS. Its four forms are: lay (present); laid (past); has, have, or had laid (participle); and laying (gerund). Examples are:

Please lay that lamp down. (present)
That hen should lay one egg daily. (present)

She laid that lamp down yesterday. (past)
That hen laid three eggs last week. (past)

She has laid that lamp down every day for the past week. (participle)
That hen has laid only three eggs a week for a month. (participle)

Laying heavy lamps on tables is very strenuous. (gerund)
Laying eggs outside the chicken coop is not profitable. (gerund)

(N.B. - To lie also means: to tell an untruth. Those four forms are lie, lied, lied, and lying; but I don't think many people have a problem using "lie" with that meaning.)