"Laid" Or "Lain"?
Lay is the present tense of a verb whose basic meaning is ‘place something in a more or less horizontal position’, with the past tense and participle laid.
So the proper use is:
|present tense||Please lay it on the floor.||Go and lie down.|
|past tense||She laid the book on the desk.||She went and lay down.|
|past participle||They had laid it on the floor.||The body had lain in the field for some time.|
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