Liam is 'very ill' [verbal complement or subject complement?]

[Listenever]

Liam is very ill. (English Syntax and Argumentation, Bas Aarts)

Traditional Grammar says ‘very ill’ as a subject complement.
And the book says ‘very ill’ as a complement for verb be.

Do I have to accept the remark as ‘Liam is’ can’t complete a sentence,
so the verb needs a complement. Or the complement modifies the verb?

 

[lucas-sp]

There are two different meanings of the verb "to be."

1. "Liam is." Here "to be" means "to exist." "Liam exists" is a complete sentence, and "Liam is" is thus a complete sentence when "is" means "exists."

2. "Liam is ill." Here "to be" links the subject and its complement. As a linking verb, it needs a complement after it. It's up to you whether you think that "ill" is the complement of "Liam" or "is" - choose whatever you find more helpful. If "to be" is a linking verb, then "Liam is" is not a complete sentence - "Liam is" is only a complete sentence if "is" is existential. Compare this to: "Liam seems tired." "Liam seems" is obviously not a complete sentence. "Seems" can only be a linking verb, so some complement is needed in the sentence.