The compound nominal predicate always consists of a link verb (also called copula) and a predicative, which may be expressed by various parts of speech, usually a noun, an adjective, also a stative, or an adverb (as in the sentence The lesson is over). Often enough the predicative is represented by a phrase, most usually of the pattern "preposition + noun", which may or may not be a phraseological unit.
Now we must find the characteristic features of a link verb. It should first of all be noted that the term "link verb" (as well as the term "copula", after which it appears to have been coined) is not a very happy one. The idea of "link" suggests that its function is to connect the predicative with the subject. This, however, is hardly intelligible. Why should the predicative need some special word to connect it with the subject? It could stand side by side with the subject without the help of any "link". Indeed it does not require any link in sentences with the simple nominal predicate which we have discussed on p. 208 ff., and this is still more usual in Russian, where no link verb as a rule appears in the present tense. The true function of a link verb is notconnecting function. It expresses the tense and the mood in the predicate. The link verb be, which expresses these categories, and also those of number and person, is rightly considered to be the most abstract of all link verbs, that is, the one most devoid of any meaning of its own. Other link verbs have each some lexical meaning.
Though the term "link verb" is purely conventional, we will retain it, as it is in common use and an attempt to substitute another term would stand little chance of success.
Besides the verb be there are a number of other link verbs with different meanings which we need not discuss here, for instance become, get, continue, grow, turn, e. g. Then he grew thirsty and went indoors (LINKLATER); But presently the sea turned rough (Idem), etc. It will be readily seen that some of them do not always perform this function but may also be a predicate in themselves, for instance the verb grow in the sentences The child has grown, or, We grow potatoes. Of course it is only the meaning of the noun following the verb that shows whether the noun is a predicative or an object: compare the two sentences They have grown fine young men and They grow potatoes. So if we say that a verb is a link verb this need not necessarily mean that it is always a link verb and cannot perform any other function.
To approach the subject of link verb and predicative from another angle, we may say that if a verb is followed by a predicative it is, to some extent at least, a link verb. The restriction "to some extent at least" is necessary because there are sentences in which the finite verb is a predicate in itself, that is, it contains some information about the subject which may be taken separately, but at the same time the verb is followed by a predicative (a noun or an adjective) and is in so far a link verb. This is found in sentences like the following: He came home tired, She married young, He died a bachelor, etc. The finite verb in such sentences conveys a meaning of its own (he came, she married, he died), but the main point of the sentence lies in the information conveyed by the predicative noun or adjective. We might retell the meaning of these sentences in another way, namely: He was tired when he came home, She was young when she married, He was a bachelor when he died, etc. The finite verb, besides being a predicate in itself, also performs the function of a link verb.
Since such sentences have both a simple verbal predicate and a compound nominal predicate, they form a special or mixed type: predicates of this kind may be termed double predicates. 1 Here are some examples:
Sunlight seeped thick and golden through the high, oblong windows above the cages and fell in broad shafts to the linoleum floor where he dropped his bucket. (BUECHNER) Compare also the following sentence: Catherine's blood ran cold with the horrid suggestions which naturally sprang from these words. (J. AUSTEN) The lexical meaning of the verb run is here almost wholly obliterated, as will also be seen by translating the sentence into Russian, or, indeed, any other language. The essence of the predication is of course contained in the predicative adjective cold.
Let us now look at a few more examples of sentences with a predicative coming after a full predicate with secondary parts attached to it. She had set her feet upon that road a spoiled, selfish and untried girl, full of youth, warm of emotion, easily bewildered by life. (DREISER) A spoiled, selfish, and untried girl is a predicative, coming after a fully developed predicate group consisting of the predicate itself, an object and an adverbial modifier. That the group a spoiled, selfish and untried girl is a predicative, is clear, because no other syntactical tie between this group and the preceding words in the sentence can be imagined. It is a peculiarity of this sentence that the predicative has three loose attributes belonging to it: full of youth, warm of emotion, and easily bewildered by life. They make this predicative group very weighty indeed. It may also be noted that the predicative group a spoiled, selfish and untried girl, full of youth, warm of emotion, easily bewildered by life represents the rheme of the sentence, while the preceding words in the sentence represent its theme. Indeed, the contents, or the purpose of the sentence, is not to inform the reader that she had set her feet on that road, but what kind of person she was at the time she did so. If the predicative (with its secondary parts) were to be dropped, the communication value of the sentence would be basically changed, and in the context in which it stands its value would be reduced to nought.
The same is found in the following examples: You've come home such a beautiful lady. (TAYLOR) I sat down hungry, I was hungry while I ate, and I got up from the table hungry. (SAROYAN)
It should also be noted that the verb preceding the predicative and therefore performing (at least partly) the function of a link verb, may be in the passive voice. This is especially true of the verbs find, think, report, as in the sentences, He was found guilty, He was reported dead, etc.
From such sentences there is an easy transition to sentences in which the finite verb is followed by an infinitive, as in He was known to have arrived, etc.
It may be the infinitive of the verb be, which is then in its turn followed by a predicative (a noun or an adjective), for instance, He was said to be a great actor, He was reported to be dead, etc.
As far as meaning is concerned, there seems to be no difference between the sentences He was reported dead, and He was reported to be dead, or between the sentences He seemed clever and He seemed to be clever. As far as structure is concerned, the second variant in each case is somewhat more complicated, in that the finite verb is first followed by an infinitive, which apparently is bound to be a predicative (since it comes after the link verb), but which is itself the infinitive of a link verb and therefore followed by another predicative.
Besides the combinations of different predicates, already mentioned various other combinations are possible and actually occur in texts. However, finding out all these possibilities is of no particular scientific interest. 1
1 We shall have to touch on another question connected with the predicate after examining the secondary parts of the sentence (see p. 237 ff,).