The advervials are optional.
Hi, I am not sure I understand you here. Would you elaborate, please?
We can predicate a location:
He is in the room.
I've been in the garden all the time since lunch.
in the garden (subjective complement)
all the time (adverbial)
since lunch (adverbial)
According to Quirk in CGEL (
1985), in the garden is not a complement, but an obligatory adverbial, an obligatory predicate adjunct (SVA). With copula verbs, the adverbial is always obligatory. On the other hand, predicate adjuncts can be obligatory or optional with verbs other than CopV.
Compare:
She put the letter on the kitchen table. :tick: = SVOA
She put the letter [STRIKE]on the kitchen table[/STRIKE]. :cross:
She found the letter on the kitchen table. :tick: = SVO
She found the letter [STRIKE]on the kitchen table[/STRIKE]. :tick: = SVO
I've been in the garden all the time since lunch.
in the garden (subjective complement)
all the time (adverbial)
since lunch (adverbial)
'in the garden' is an adverbial. It is an adjunct of space which is obligatorily present in the sentence. It is the
A in your SV
A sentence and so enters the valency pattern of the copula verb 'have been'.
However, 'nice' in 'He is nice' is a
C, a predicate adjective, in SV
C, and 'Peter' in 'He is Peter' is a C in SVC, a predicate nominative. Subject complement is a grammatical term that includes predicate adjectives and predicate nominatives as its two subtypes.
a. all the time (adverbial)
and optional
b. since lunch (adverbial)
and optional
These two optional adverbials above (a. and b.) are not included in the valency pattern of the copula verb 'have been'.