The present tense is relatively easy: "lay" requires an object (you lay a book on the table), and "lie" doesn't (you lie on the sofa). The past tense and participles get so confusing though that we made a chart!
3. 'Lay' Versus 'Lie' in the Past Tense
But then everything goes all haywire, because "lay" is the past tense of "lie." It's a nightmare! I tried and tried to come up with a mnemonic for this, but I couldn't do it. Instead, I've made a table that you can print out from the website and tape up over your desk or in your notebook, because you just have to memorize this or look it up every time.
4. How to Conjugate 'Lay' and 'Lie'
Here's how to conjugate these two verbs:
The past tense of "lie" is "lay."
Last week, Steve lay down on the floor.
The cat lay in the mud after it rained yesterday.
The past tense of "lay" is "laid."
Last week, I laid the TPS report on your desk.
Mary forcefully laid her ring on the table.
The past participle of "lie" is "lain."
Steve has lain on the floor for days.
The cat has lain in the mud for hours.
The past participle of "lay" is also "laid."
I have laid the TPS report on your desk.
Mary has forcefully laid her ring on the table.
Don't feel bad if you can't remember these right away. Practice will help, and truthfully, I still have to look them up every time I use them. It's just important to know what you know, and what you don't know, and to go to the trouble to look it up and get it right because these are hard-and-fast rules.
Download the Chapter on 'Dirty Words' From Grammar Girl's Book
"Lay" versus "lie" is just one of the many confusing word choices that Mignon Fogarty covers in the "Dirty Words" chapter of her book, "Grammar Girl's Quick and Dirty Tips for Better Writing." You can download the chapter by clicking here.
The book is also available in an e-book edition. You can download a copy wherever e-books are sold.
Think you understand the difference between "lay" and "lie"? Take the quiz!