Here's why:
* Linking verbs connect the subject of a sentence to a word or phrase that renames or describes it.
* Predicate nominatives are nouns or pronouns that rename the subject.
Examples:
* She is a doctor. ("is" is the linking verb, "doctor" is the predicate nominative, renaming "she")
* The winner was he. ("was" is the linking verb, "he" is the predicate nominative, renaming "winner")
* My favorite color is blue. ("is" is the linking verb, "blue" is the predicate nominative, describing "color")
Common linking verbs:
* be (am, is, are, was, were, be, being, been)
* appear
* become
* feel
* grow
* look
* remain
* seem
* smell
* sound
* taste
Remember, the predicate nominative must be linked to the subject by a linking verb. If there is no linking verb, the word following the subject is not a predicate nominative.