Question

The tree by the lake is an oak. The predicate noun in this sentence is _____.

Answer 1

Answer:

is an

Explanation:

A predicate noun is a single noun or a noun phrase that renames the subject of a sentence and follows a form of the verb "to be" or another linking verb.

Answer 2

Answer:

an oak

Explanation:

A predicate noun usually have a verb that precedes it in a sentence. This verb is usually known as linking verbs. A predicate noun is usually a noun phrase.

In the given example;

"The tree by the lake is an oak"

Is serves as the linking verb.  

an oak is the predicate noun because it contains a noun phrase and which renames the subject "The tree"