Hey Ootred, The sentence 'lying on the ground' would be the correct one in that context. Both 'lay' and 'lie' mean the same but grammatically they behave differently: 'lay' needs an object (for example: someone (subject) is laying (verb) something (object) down) while 'lie' is intransitive, it does not need an object (like in the case of your structure 'the man (subject) was lying (verb) on the ground'). Hope that is helpful for you. Do not hesitate to contact me for more information Oana

Oana Maria gave a good answer. To lie and to lay are frequently confused by native speakers. to lie He lies in bed. He lay in bed for hours. He has lain in bed for hours. to lay [something] [somewhere] He lays the book on the table. He laid the book on the table. He has laid the book on the table.

Not sure, I think you would either have to make a presumption the teenager had something to do with Portillo laying on the ground or did the man lie down himself. Feel free to use either, this would only be a distinction a English professor or teacher would care about.