Definition:


Linking verbs or copular verbs link a subject to a complement. Linking verbs MUST be followed by a complement in order to make the sentence complete. The complement can be a subject complement or an adverbial, and occurs in two sentence types which are of the Subject-Verb-Complement (SVC) and Subject-Verb-Adverbial (SVA) pattern.


Types:


There are two groups of linking verbs: current linking verbs and resulting linking verbs.

Current linking verbs indicate a state. (current linking verbs) Resulting linking verbs indicate that the role of the verb complement is a result of the process described in the verb. (resulting linking verbs)



Sentence Patterns:
Subject-Verb-Complement
We can distinguish the following patterns:

A. The complement is a noun phrase or noun clause:

This is a really nice outfit.
The anwer is that we don't want to go to the party.
He became a beggar.
B. To be can occur between the linking verb and the complement. Although this "to be" is not necessary, both American English and British English prefer an infinitive construction with to be rather than simply a noun phrase.

She seems (to be) all right.
He proved (to be) a good husband.
She appears (to be) exhausted.
NOTE:

a) There is also a tendency , especially in AME, to prefer a construction in which the verb is followed by like:

 
thanks my brother for the honest ducumentation.and the good topic