Agreement of Verb with its Subject. The verb should agree with its subject in person and number. The most frequent error is the failure of the verb to agree in number with its subject. Singular subjects are used with plural verbs, and plural subjects with singular verbs. These errors arise chiefly from a misapprehension of the true number of the subject.
The s-form of the verb is the only distinct singular form, and occurs only in the third person, singular, present indicative; as, He runs, she goes, it moves. Is, was, and has are the singular forms of the auxiliaries. Am is used only with a subject in the first person, and is not a source of confusion. The other auxiliaries have no singular forms.
Failure of the verb and its subject to agree in person seldom occurs, and so can cause little confusion.
Examine the following correct forms of agreement of verb and subject:
A barrel of clothes was shipped (not were shipped).
A man and a woman have been here (not has been here).
Boxes are scarce (not is scarce).
When were the brothers here (not when was)?
Agreement of Subject and Verb in Number. The general rule to be borne in mind in regard to number, is that it is the meaning and not the form of the subject that determines whether to use the singular or the plural form of the verb. This rule also applies to the use of singular or plural pronouns.
Many nouns plural in form are singular in meaning; as, politics, measles, news, etc.
Many, also, are treated as plurals, though in meaning they are singular; as, forceps, tongs, trousers.
Some nouns, singular in form, are, according to the sense in which, they are used, either singular or plural in meaning; as, committee, family, pair, jury, assembly, means. The following sentences are all correct: The assembly has closed its meeting, The assembly are all total abstainers, The whole family is a famous one, The whole family are sick.
In the use of the adjective pronouns, some, each, etc., the noun is often omitted. When this is done, error is often made by using the wrong number of the verb. Each, either, neither, this, that, and one, when used alone as subjects, require singular verbs. All, those, these, few, many, always require plural verbs. Any, none, and some may take either singular or plural verbs. In most of these cases, as is true throughout the subject of agreement in number, reason will determine the form to be used.
Some nouns in a plural form express quantity rather than number. When quantity is plainly intended the singular verb should be used. Examine the following sentences; each is correct: Three drops of medicine is a dose, Ten thousand tons of coal was purchased by the firm, Two hundred dollars was the amount of the collection, Two hundred silver dollars were in the collection.
The following rules govern the agreement of the verb with a compound subject:
1. When a singular noun is modified by two adjectives so as to mean two distinct things, the verb should be in the plural; as, French and German literature are studied.
2. When the verb applies to the different parts of the compound subject, the plural form of the verb should be used; as, John and Harry are still to come.
3. When the verb applies to one subject and not to the others, it should agree with that subject to which it applies; as, The employee, and not the employers, was to blame, The employers, and not the employee, were to blame, The boy, as well as his sisters, deserves praise.
4. When the verb applies separately to several subjects, each in the singular, the verb should be singular; as, Each book and each paper was in its place, No help and no hope is found for him, Either one or the other is he, Neither one nor the other is he.
5. When the verb applies separately to several subjects, some of which are singular and some plural, it should agree with the subject nearest to it; as, Neither the boy, nor his sisters deserve praise, Neither the sisters nor the boy deserves praise.
6. When a verb separates its subjects, it should agree with the first; as, The leader was slain and all his men, The men were slain, and also the leader.
Some miscellaneous cautions in regard to agreement in number:
1. Do not use a plural verb after a singular subject modified by an adjective phrase; as, The thief, with all his booty, was captured.
2. Do not use a singular form of the verb after you and they. Say: You were, they are, they were, etc., not, you was, they was, etc.
3. Do not mistake a noun modifier for the noun subject. In the sentence, The sale of boxes was increased, sale, not boxes, is the subject of the verb.
4. When the subject is a relative pronoun, the number and the person of the antecedent determine the number and the person of the verb. Both of the following sentences are correct: He is the only one of the men that is to be trusted, He is one of those men that are to be trusted. It is to be remembered that the singulars and the plurals of the relative pronouns are alike in form; that, who, etc., may refer to one or more than one.
5. Do not use incorrect contractions of the verb with not. Don't cannot be used with he or she or it, or with any other singular subject in the third person. One should say, He doesn't, not he don't; it doesn't, not it don't; man doesn't, not man don't. The proper form of the verb that is being contracted in these instances is does, not do. Ain't and hain't are always wrong; no such contractions are recognized. Such colloquial contractions as don't, can't, etc., should not be used at all in formal composition.