Studying the Rules of Subject Verb Agreement
I hope to share this post to all my students in English. Hope this will be a good reference to you all. 
RULES ON
SUBJECT-VERB AGREEMENT
Rule 1: Basic Principle - Singular subjects need singular verbs; plural subjects need plural verbs.
- My brother is a nutritionist. My sisters are mathematicians.
Rule 2: The indefinite pronouns anyone, everyone, someone, no one, nobody are always singular and, therefore, require sigular verbs.
- Everyone has done his or her homework.
- Somebody has left her purse.
Rule 3 : Some indefinite pronouns — such as all, some — are singular or plural depending on what they’re referring to. (Is the thing referred to countable or not?) Be careful choosing a verb to accompany such pronouns.
- Some of the beads are missing.
- Some of the water is gone.
Rule 4 : On the other hand, there is one indefinite pronoun, none, that can be either singular or plural; it often doesn’t matter whether you use a singular or a plural verb — unless something else in the sentence determines its number.
- None of you claims responsibility for this incident?
- None of you claim responsibility for this incident?
- None of the students have done their homework.
- The mayor as well as his brothers is going to prison.
- The mayor and his brothers are going to jail.
Rule 5 : Phrases such as together with, as well as, and along with are not the same as and. The phrase introduced by as well as or along with will modify the earlier word (mayor in this case), but it does not compound the subjects (as the word and would do).
Rule 6 : The pronouns neither and either are singular and require singular verbs even though they seem to be referring, in a sense, to two things.
- Neither of the two traffic lights is working.
- Which shirt do you want for Christmas?
Either is fine with me.
Rule 7 : In informal writing, neither and either sometimes take a plural verb when these pronouns are followed by a prepositional phrase beginning with of. This is particularly true of interrogative constructions
- Have either of you two clowns read the assignment?
- Are either of you taking this seriously?
Rule 8 : The conjunction or does not conjoin (as and does). When nor or or is used the subject closer to the verb determines the number of the verb.
- Either my father or my brothers are going to sell the house.
- Neither my brothers nor my father is going to sell the house.
- Are either my brothers or my father responsible?
- Is either my father or my brothers responsible?
Rule 9 : The words there and here are never subjects.
- There are two reasons [plural subject] for this.
- There is no reason for this.
- Here are two apples.
Rule 10 : Verbs in the present tense for third-person, singular subjects (he, she, it and anything those words can stand for) have s-endings. Other verbs do not add s-endings.
- He loves and she loves and they love_ and . . . .
Rule 11 : Sometimes modifiers will get between a subject and its verb, but these modifiers must not confuse the agreement between the subject and its verb.
- The mayor, who has been convicted along with his four brothers on four counts of various crimes but who also seems, like a cat, to have several political lives, is finally going to jail.
Rule 12 : Words such as glasses, pants, pliers, and scissors are regarded as plural (and require plural verbs) unless they’re preceded by the phrase pair of (in which case the word pair becomes the subject).
- My glasses were on the bed.
- My pants were torn.
- A pair of plaid trousers is in the closet.
Rule 13 : Some words end in -s and appear to be plural but are really singular and require singular verbs.
- The news from the front is bad.
- Measles is a dangerous disease for pregnant women.
Rule 14 : On the other hand, some words ending in -s refer to a single thing but are nonetheless plural and require a plural verb.
- My assets were wiped out in the depression.
- The average worker’s earnings have gone up dramatically.
- Our thanks go to the workers who supported the union.
Rule 15 : Fractional expressions such as half of, a part of, a percentage of, a majority of are sometimes singular and sometimes plural, depending on the meaning.
- A large percentage of the older population is voting against her.
- Two-fifths of the troops were lost in the battle.
- Two-fifths of the vineyard was destroyed by fire.
- Forty percent of the students are in favor of changing the policy.
- Forty percent of the student body is in favor of changing the policy
Rule 16 : Sums and products of mathematical processes are expressed as singular and require singular verbs. The expression "more than one" (oddly enough) takes a singular verb.
- More than one student has tried this.
- Two and two is four.
- Four times four divided by two is eight.
Rule 17 : If your sentence compounds a positive and a negative subject and one is plural, the other singular, the verb should agree with the positive subject.
- The department members but not the chair have decided not to teach on Valentine’s Day.
- It is not the faculty members but the president who decides this issue.
- It was the speaker, not his ideas, that has provoked the students to riot.
