英文文法問題lay

I saw my dad sleeping in the room; he lay motionless on the sofa.

"motionless" is an adjective.

You can use "lie" as a linking verb to say that something is or remains in a particular state or condition.

pattern: :~ linking verb + adjective (In this case, lie + adjective)

The book lay open on the table.
lay ~ past tense of lie (linking verb)
open ~ adjective

This machine lies idle.
lies ~ linking verb
idle ~ adjective

4000 men lie buried here.
lie ~ linking verb
buried ~ past participle of "bury"
~ past participle used as an adjective



2013-10-10 23:03:54 補充：
“The horse lay motionless on the ground, as if dead”
http://dictionary.cambridge.org/dictionary/british/motionless

“He lay motionless at her feet.”
http://blogs.dctc.edu/writing-center/2011/01/31/lie-vs-lay-the-controversy-unveiled/

“He lay motionless on the bed.” ~ Macmillan English Dictionary

2013-10-10 23:05:48 補充：
Other examples: lie + adjective
“He lies awake at night worrying about his job.” ~ Oxford English Dictionary
“Emma lay awake half the night, worrying.” ~ Longman English Dictionary
“awake” is an adjective

2013-10-11 00:38:56 補充：
Longman 和 Collins Colbuild 字典, 分開列 lie 可作 linking verb
若用adverb, 只可 describe 動詞 "lie", how someone lies. 當 lie 是 intran. verb 或 link. verb?
用 link. verb, 形容詞 "motionless" 是 condition he was in.
In my past learning, I always write "lie motionless". Taste is too individual to be standardized.

He lay motionlessly on the sofa.- adverb

He was motionless and slept on the sofa. - adjective

Why do you think that we can not use "motionlessly" ?

I think we do have to use "motionlessly", because it is an adverb, for describing the verb "lay". "Motionless" is an adjective. We cannot use an adjective to describe a verb, only a noun, so we can say "he was on the sofa, motionless", but that does not specify that he actually lay on the sofa. In fact he could have fallen asleep while sitting on the sofa.

Therefore, in order to describe the whole scenario, we can say:
A:
1. He lay motionlessly on the sofa.
or B.
1. He lay on the sofa.
2. He was motionless.