A verb must agree with its subject in number and person. Such a relation is called subject verb agreement.
RULES REGARDING SUBJECT – VERB AGREEMENT
• Two or more singular nouns or pronouns joined by ‘and’ require a plural verb.
Haryana and Punjab share the same capital.
• If the nouns suggest ‘one idea’ to the mind, or refer to the same person or thing, the verb is singular.
Dal and rice is a staple diet in South Asia.
• Words joined to a singular subject by ‘with, as well as’, etc. are parenthetical. The verb should therefore be put in the singular.
The shepherd, along with his sheep, is out in the sun.
• Two or more singular subjects connected by ‘either…or’ or ‘neither…nor require a singular verb.
Neither the bench nor the desk is big enough.
• When one of the subjects joined by ‘either…or’ or ‘neither…nor is plural, the verb must be plural, and the plural subject should be placed close to the verb.
Neither the final nor the league matches were interesting.
• When the subjects joined by ‘either…or’ or ‘neither…nor are of different persons, the verb agrees with the nearer one.
Neither you nor she eats quietly.
• Either, neither, each, everyone and many a must be followed by a singular verb.
Every one of them is meant for sale.
• Two nouns qualified by each or every, even though connected by and, require a singular verb.
Every school and every college was closed.
• Some nouns which are plural in form, but singular in meaning, take a singular verb.
The genesis of obesity lies in bad eating habits.
• When the plural noun is a proper name for some single object or some collective unit, it must be followed by a singular verb.
'Lions for Lambs' has Tom Cruise playing the role of a senator.
• When a plural noun denotes some specific quantity or amount considered as a whole, the verb is generally singular.
Ten wickets in an innings is a record that belongs to him.
• In the sense of income, the word means always takes a plural verb.
Your means proliferate when you work hard.
• None, though properly singular, commonly takes a plural verb.
Water is the ultimate drink; none offer more respite.
• Some nouns which are singular in form, but plural in meaning take a plural verb.
Three score cost one hundred and fifty rupees.
• A Collective Noun takes a singular verb when the collection is thought of as one whole; plural verb when the individuals of which it is composed are thought of.
The committee is about to make a decision.