Roy Peter Clark, in his excellent guide to practical writing The Glamour of Grammar, offers the following advice on two of the trickiest homophones in the English language, lie and lay —
Here’s the simplest way to remember the difference: lie means “to recline”; lay means “to place.” As in “I lay the cushions on the floor so I can recline in comfort.” (You can use the vowel sounds as a memory aid: lie/recline; lay/place.)
Confusion sweeps in when we move from the present tense to the past. Alas, the past tense of lie happens to by lay: “When I heard the news, I lay on the bed in disbelief.” And the past tense of lay is laid, as in “The bank robbers laid their weapons on the ground.”
Clark then gives us the following helpful examples that distinguish the principal parts of these tricky irregular verbs —
Lie: Today I lie on the bed. Yesterday I lay on the bed. I have lain on that bed so many times there are holes in the mattress.
Lay: Today I lay my cards on the table. Yesterday I laid my cards on the table. I have laid my cards on the table so many times that I was bound to win.
Significantly, Clark uses lie and lay as part of a larger discussion about how a writer can master irregular verbs. He suggests that learning the principal parts of these verbs and understanding the distinction between transitive and intransitive verbs will help writers to communicate more clearly. (The Glamour of Grammar is a fantastic book, by the way, and would make a vital addition to the libraries of experience and inexperienced writers alike).
So, ready for a quiz? One of our favorite blogs, Ironic Sans, compiled every use and misuse of lay and lie from the first three seasons of Mad Men. You’ll have a moment after hearing a character use or misuse lay or lie to decide if he or she has done so with grammatic fidelity. After that, a graphic (and sound) will let you know if the word has been used correctly. Good luck!