Language has its base in logic and harmony. The subject and verb are the essential parts of a sentence. The verb should agree with the subject in number and person.

Remember these points:

1. Two or more singular subjects connected by 'and' usually take a plural verb.
Examples :
[a] Rahul and Ram are present.
[b] Ajith and I are Friends.
[c] Two and two make four.
2. If two singular words refer to the same person or thing or suggest one idea the verb must be singular.
Examples :
[a] My Friend and patron has come
[b] Slow and steady wins the race.
[c] Rice and curry is my favorite dish.
3. A singular verb must be used with a singular subject and a plural verb is used with a plural subject. But remember many singular VERBS and plural NOUNS end with the letter 's'
Examples :
[a] The Cat dreams about chasing mice.
[b] The Cats dream about chasing mice
4. It the singular subjects are preceded by 'each' or 'every', use singular verb.
Examples :
[a] Every boy and girl was ready
5. Two or more singular subjects connected by 'or' 'nor', 'either', 'neither' take a verb in the singular.
Examples :
[a] No nook or corner was left unexplored.
6. A singular subject and a plural subject joined by 'or' or 'nor' will take a verb depending on which subject is nearer the verb.
Examples :
[a] Neither Deepu nor his friends are joining the party.
[b] Neither his friends nor Deepu is joining the party.
7. Indefinite pronouns such as someone, somebody, anyone, anybody, nobody, one no one, everyone, everybody, either, neither, etc. always take a singular verb.
Examples :
[a] Each of my Friends call me once a month.
8. Indefinite pronouns which indicate more than one, such as several, both, many always take plural verbs.
Examples :
[a] Both of the books are worth reading
[b] Several of the athletes run four or five kilometres a day.
9. Collective nouns are singular when they works together as a unit and take singular verbs.
Examples :
[a] The mob has gathered quickly.
[b] The team runs in a smooth way.
10. Collective nouns are plural when the members of the group are acting individually and take a plural verb.
Examples :
[a] The jury have argued for a long time.
[b] The team are putting on their uniform.
11. Some nouns, which are plural in form but singular in meaning, take a singular verb
Examples :
[a] The news is true
12. Some words end in 's' but represent a single thing. Measles, mumps, news etc. These words need singular verb.
Examples :
[a] The scissors are on the table
[b] His trousers are very costly.
13. Words such as Mathematics, Politics, ethics, athletics are singular, they take singular verbs.
Examples :
[a] Politics is a dirty game
[b] mathematics is his favourite subject
14. If these words have modifiers with them they become plural and take plural verbs.
Examples :
[a] His politics are somewhat divided
[b] The mathematics of the tax return are flawless.
[c] The school's athletics are all for both boys and gir.s
15. Title of the books need singular verbs.
Examples :
[a] "Tom Jones" is a book of Fielding.
16. Some nouns in the plural form represent an amount, a fraction or an element of time. These nouns are considered singular and take singular verbs.
Examples :
[a] Thirty minutes is enough to complete this work.
[b] Three-fourths of the land is cultivable.
17. If two subjects are joined by 'as well as' the verb will act according to the first subject.
Examples :
[a] Students as well as the teacher are reading.
[b] Teacher as well as the students is reading.
[c] I as well as he am going out for a walk.
18.The subject 'Many a' is always followed by a singular verb.
Examples :
[a] Many a man does not known his own interests
19. If two subjects are joined together by 'with' the verb will act according to the subject.
Examples :
[a] The Principal together with the students is watching the play
[b] The students together with the Principal are watching the play.
20. If the subject is 'The number of' use a singular verb.
Examples :
[a] The number of books is very small
21. If the subject begins with 'A number of' use plural verb.
Examples :
[a] A number of questions were asked in the interview.
22. If two subjects express one idea, use singular verb.
Examples :
[a] Soup and salad is my favourite lunch
[b] Bread and butter is a wholesome food.
23. When adjectives such as much, less, little and more are used as nouns, use singular verb.
Examples :
[a] A little or good habits makes our life happy.
[b] Less than a lakh of rupees is required.