Position of Adjectives: An adjective nearly always appears immediately before the noun or noun phrase that they modify. The source is here.
- He was knocked unconscious by a fall.
- An injured motorcyclist is lying unconscious in the road.
- She was unconscious for three days after the accident.
In the 2nd sentence, why can't it be "unconsciously"? Lying is a verb, so "lying unconsciously" is valid, is itn't?