There are 9 parts of speech or word classes in English language:
– nouns
– pronouns
– determiners
– verbs
– prepositions
– adjectives
– adverbs
– conjunctions
– interjections

Subject-Verb Agreement is a set of rules that must be followed to ensure consistency of sentence subject and verb form in a sentence.

In English, one complete sentence must have at least:
– one subject
– one verb

Verbs in English sentences are very sensitive to subjects.
The form of a verb follow what or who the subject of the sentence is.

1. If the subject of a sentence is singular, we use a singular verb after the subject.

He is a doctor.
He are a doctor. (wrong)

She writes every day.
She write every day. (wrong)

2. If the subject of a sentence is plural, we use a plural verb after the subject.

They are doctors.
They is doctors. (wrong)

We write every day.
We writes every day. (wrong)

3. If the subject of a sentence consists of 2 nouns/pronouns or more and they are connected to each other with conjunction ‘and’, we use a plural verb after the subject.

He and his daughter are Javanese.
He and his daughter is Javanese. (wrong)

John and Paula run every Sunday.
John and Paula runs every Sunday. (wrong)

4. If the subject of a sentence consists of 2 nouns/pronouns or more and they are connected to each other with conjunction ‘or’, we use a singular verb after the subject.

That girl or that boy is going to help.
That girl or that boy are going to help. (wrong)

Neither he nor his sister is at home.
Neither he nor his sister are at home. (wrong)

5. If the subject of a sentence consists of 1 singular subject and 1 plural subject, and they are connected to each other with conjunction ‘or’ or ‘nor’, the verb form follows the subject nearest to the verb.

The boy or his friends run every day.
The boy or his friends runs every day. (wrong)

His friends or the boy runs every day.
His friends or the boy run every day. (wrong)

The boy or his friends are going to come.
The boy or his friends is going to come. (wrong)

His friends or the boy is going to come.
His friends or the boy are going to come. (wrong)

6. If there is 1 subject with more than 1 verb, the forms of all the verbs follow the subject.

Interviews are one way to collect data and allow researchers to gain an
in-depth understanding of participants.
Interviews are one way to collect data and allows researchers to gain an
in-depth understanding of participants. (wrong)

7. If there is a phrase between a subject and a verb, the form of the verb follows the subject and is not affected by the noun or pronoun in the phrase.

A virus in all the company’s computers is a real threat to security.
A virus in all the company’s computers are a real threat to security. (wrong)

The table and chair I got at the store look really nice in here.
The table and chair I got at the store looks really nice in here. (wrong)

8. If the subject of a sentence is a singular indefinite pronoun, we a singular verb.

Singular indefinite pronouns;
– somebody, anybody, everybody, nobody
– someone, anyone, everyone, no one
– something, anything, everything, nothing

Everybody loves Sally.
Everybody love Sally. (wrong)

Everything was ready for the party.
Everything were ready for the party. (wrong)

9. If the subject of a sentence is a plural indefinite pronoun, we a plural verb.

Singular indefinite pronouns;
– both, many, few, several

I invited Kid and Nid and both want to come.
I invited Kid and Nid and both wants to come. (wrong)

A lot of people are attending the party. Many have already left.
A lot of people are attending the party. Many has already left. (wrong)

10. Some indefinite pronouns / determiners can be followed by singular verbs or plural verbs depending whether the subject is a countable noun or an uncountable noun;
– some, any, all, most, more

Some employees were there yesterday.
Some employees was there yesterday. (wrong)

Some money was missing from the store.
Some money were missing from the store. (wrong)

A lot of people have arrived. More are coming.
A lot of people have arrived. More is coming. (wrong)

We found a lot of information but more is needed.
We found a lot of information but more are needed. (wrong)

11. If the subject of a sentence contains ‘each’, ‘every’, ‘either’, or ‘neither’, we use a singular verb.

Each answer is wrong.
Each answer are wrong. (wrong)

Either answer is correct.
Either answer are correct. (wrong)

12. If the subject of a sentence is an uncountable noun, we use a singular verb.

Happiness is the key to success.
Happiness are the key to success. (wrong)

Sugar needs to be added carefully.
Sugar need to be added carefully. (wrong)

13. If a sentence starts with ‘there’ or ‘here’, the real subject is after the verb.

There is a problem at the factory.
– a problem = subject

There are problems at the factory.
– problems = subject

Here is the key.
– the key = subject

Here are the keys.
– the keys = subject

14. If there is a fraction or percentage in a sentence, the form of the verb follows the noun type of the subject
– countable noun (singular / plural)
– uncountable noun

Three-quarters of the building was destroyed. (singular countable noun)
Three-quarters of the building were destroyed. (wrong)

Seventy-five percent of the buildings were destroyed. (plural countable noun)
Seventy-five percent of the buildings was destroyed. (wrong)

Half of the wine comes from France. (uncountable noun)
Half of the wine come from France. (wrong)

Fifty percent of the wine is bad. (uncountable noun)
Fifty percent of the wine are bad. (wrong)

15. If the subject of a sentence is a collective noun (a word that means more than one person but is considered as a group), we use a singular verb.
– team, committee, family, crew

The group meets every week.
The group meet every week. (wrong)

The committee is having a meeting right now.
The committee are having a meeting right now. (wrong)