Subject verb agreement-
A verb describes an action or a state of being. A verb must always agree with its subject, in person and in number. Rules that to be kept in mind are:
1. When two subjects are joined by the conjunction “and”, the subject becomes plural;hence the verb must be plural in form. For example:
My son and daughter are equally good at English.
2. In case of two singular nouns referring to the same person, the verb must be singular. For example:
The minister and economist has been hospitalised after the accident.
3. If the subject is preceded by the words like 'each', 'every', 'any' etc. then the verb must be singular in form. For example:
Each of the students has done well in the examination.
4. More than one plural subject joined by 'either-or', 'neither-nor' must take a singular verb. For example:
Neither he nor I was allowed to enter the class.
5. A collective noun takes a singular verb. For example:
The committee has agreed to our demands.
(Note: A collective noun takes a plural verb when the components of the collection are spoken of as separate. For example: The Jury were divided in their opinion)