What's the difference between 'lie' and 'lay'?

The basic rule:

• "I need to lie down."
• "The cat lies on the sofa."
• Past tense: LAY. "I lay on the beach yesterday." ← This is the confusion.

• "Lay the book on the table."
• "She laid the baby in the cot."
• Past tense: LAID. "I laid the book down."

Why it's so confusing: The past tense of "lie" is "lay" — the same word as the present tense of "lay." This trips up native speakers constantly.

• Lie: lie / lay / lain
• Lay: lay / laid / laid

The honest truth: Even educated native speakers frequently say "lay down" when they mean "lie down." In casual speech, the distinction is often ignored. In formal writing, it matters.

Tags: grammar, verbs, common mistakes, lie vs lay