Does 'Is' serve as a linking verb in the following sentence?
Is it on?
Please provide reasons. Thanks
A linking verb links or connects a subject to its predicate nominative or predicate adjective.
Here, is connects it (the subject) to on (predicate adjective).
If the sentence were a statement, “It is on,” the “linking” nature of the verb would be obvious. That the sentence is a question does not change the “linking” nature of the verb.
Yes, it's known as a linking verb or "copula" as it is sometimes called. Since it creates a pure linkage, this is the reason why, technically, one should say,
"It is I." (formal)
rather than,
"It's me." (informal)
The copula "to be" links the subject "it" with its predicate. They are one and the same, i.e. "You are he" is the same as "He is you". Examples of correct English using the predicate nominative:
"It is we who must protect the earth from harm." ("We are the ones who must protect the earth from harm.")
"It is they who are to blame." ("They are the ones who are to blame.")
"It is I who am teaching this class." ("I am the one who is teaching this class.")
"It is she whom you despise." ("She is the one [whom/that] you despise.")
"You are not he who teaches this class."
However, this last one is usually written in Modern English as:
"You are not the one who teaches this class."