Lay versus Lie in the Past Tense
A chart helps us to remember the correct usage:
Present tense: lay(s)
Past tense: laid
Past participle: laid
Present participle laying
Past Tense: I laid the book on the table.
Past Participle: I had laid the book on the table.
Present Participle: Laying the book on the table, I left it there.
Present tense: lie(s)
Past tense: lay
Past participle: lain
Present participle: lying
Past Tense: Yesterday, she lay down on the couch.
Past Participle: Last week, she had lain on the couch.
Present Participle: She is lying on the couch.
Now to simplify the matter. Did you notice that the same rule we discussed concerning the present tense of lie/lay applies in the past tense as well? Lay in all tenses requires a direct object while lie in all tenses does not.