Lay and Lie: What's the Difference? Lay means to put something down. (Needs an object.) I lay my keys on the table. Lie means to rest or be in a flat position. (No object needed.) I lie on the sofa when I’m tired. Now here's where most people get confused. The past tense of lay is laid. I laid my keys on the table. The past tense of lie is lay. Yesterday, I lay on the sofa for an hour. So how about this? Last night, I ____ in bed early. Before that, I ____ my book on the desk. #englishlesson #en