Link-verbs introduce the nominal part of the predicate (the predicative) which is commonly expressed by a noun, an adjective, or a phrase of a similar semantic-grammatical character. Although they perform the function of connecting (linking) the subject and the predicative of the sentence, they are not devoid of meaningful content since they express the semantics of this connection. The linking predicator function in the purest form is effected by the verb be (the ‘pure link-verb’). All the other link-verbs express some specification of this general predicative-linking semantics (‘specifying link-verbs’). They fall into two main groups:
1) those that express perceptions (seem, appear, look, feel, taste)
2) those that express non-perceptional/factual link-verb connection (become, get, grow, remain, keep).
Besides the link-verbs proper there are some notional verbs (mostly intransitive verbs of motion and position) that can perform the function of link-verbs without losing their lexical nominative value (combining two functions simultaneously):
Fred lay awake all through the night.
Robbie ran in out of breath.
The moon rose red.
The whole predicate formed by it is referred to as a double predicate.
II) On the basis of the subject-process relation notional verbs can be divided into: