These are verbs that connect subjects to their complements( words that complete the meaning of the subjects).
The man IS a teacher(a teacher tells you about ‘the man’, so IS is a copula verb)
The interesting thing about this class of verbs is that they can be both main and auxiliary verbs. All the finite forms of the auxiliary verb TO BE are linking verbs: is, am, are, was, were.
Certain main verbs like ‘turn’ and ‘grow’ can either be linking or main:
He turned right(main)
He turned pale(linking)
In the first, ‘turned’ shows an action; in the second, it links the complement ‘pale’ to the subject it describes ‘He’.
Now, try using ‘grow’ as both a main verb and a linking verb.
