A linking verb links or connects the subject with an adjective or a noun.
Examples:
The words are, were, is, was, and am are verb forms. They are called be verbs. They are followed by the adjectives or describing words happy, angry, and bored, and by the noun, man.
When the be verbs is, are, and am are followed by describing words or nouns, they are called linking verbs.
Was is the past form of is and am.
Were is the past form of are.