It will perhaps be båst to start discussion of such sentences by considering a few characteristic examples. And then to add to the nervousness and confusion engendered by all this, thoughts as to what additional developments or persons, even, he might encounter before leaving on his climacteric errand — Roberta announcing that because of the heat and the fact that they were coming back to dinner, she would leave her hat and coat — a hat in which he had already seen the label of Braunstein ò Lycurgus — and which at the time caused him to meditate as to the wisdom of leaving or extracting it. (DREISER) This of course is a complex sentence, with several subordinate clauses in it, and the main clause is a participle clause: And then... Roberta announcing... This might admit of two different interpretations: we may take the clause with Roberta announcing as a one-member clause, Roberta the main part and announcing an attribute to it, or we may think it is a two-member clause, with Roberta the subject and announcing the predicate. What criterion shall we apply to choose between the two alternatives? If we take it as a one-member clause it would fall under the same head as some sentences we have considered above, for instance, the one from "An American Tragedy": Dusk — of a summer night, or like so many stage-directions of the type, A large room. Three chairs, etc. Now the sentence containing Roberta announcing is evidently quite different in character. It tells the fact that Roberta announced that she would leave her hat and coat, etc.
Much the same may be said of the following example: And then the next day at noon, Gun Lodge and Big Bittern itself and Clyde climbing down from the train at Gun Lodge and escorting Roberta to the waiting busf the while he assured her that since they were coming back this way, it would be best if she were to leave her bag there, while he, because of his camera as well as the lunch done up at Grass Lake and crowded into his suitcase, would take his own with him, because they would lunch on the lake. (DREISER) We need not dwell here on the subordinate clauses, which are irrelevant for our judgement of the structure of the participle clause. This example differs from the preceding in that the section of the sentence preceding the first subordinate clause, namely the text And then the next day at noon, Gun Lodge and Big Bittern itself and Clyde climbing down from the train at Gun Lodge and escorting Roberta to the waiting bus consists of two co-ordinate independent clauses, with the adverbial modifier then the next day at noon referring to both of them. The first main clause, namely Gun Lodge and Big Bittern itself, is quite clearly a one-member clause, with two co-ordinate main parts, and the second main clause a participle clause: Clydf climbing down from the train at Gun Lodge and escorting Roberta to the waiting bus. There are two participle. predicates here: (1) climbing (down), (2) escorting. Even the neighbourhood of the one-member clause Gun Lodge and Big Bittern itself cannot, it would seem, be taken as proof that the clause Clyde ... waiting bus is a one-member clause.
Such examples as these go a long way to show that the participle, though it is a verbal, not 'a finite verb form, is able to perform by itself a function generally believed to be characteristic of finite verb forms only, namely that of predicate. This possibility, as well as the ability of the infinitive to be, in certain circumstances, (he main part of a one-member sentence, should perhaps be taken into account in a definition of these forms and of verbals in general.
An additional remark may not be out of place here. In analysing sentences having an infinitive or a participle as predicate we have taken the predicate to be a nominal one. However, this view may be challenged on the ground that both the infinitive and the participle are forms of a verb, and there would seem to be some reason for claiming that the predicate of such sentences is a verbal one. It must be admitted that there are no binding reasons either way, as both the infinitive and the participle are verbals, that is, they share of the nature of a verb and of a nominal part of speech (noun or adjective). The reason why we considered such predicates to be nominal is, that an infinitive and a participle can function as predicative in connection with a link verb, and it may, at least, be argued that this shows them to be nominal elements of a predicate.