There are many rules for keeping the agreement between the subject and verb. Only the most important (which the reader can easily follow) with examples are given below:

1) If two different nouns are connected by ‘and’ then the verb should be plural. This is made clear by some examples below:

a) Smith and Micheal are great friends. Here the verb ‘is’ should not be used.

b) Health and wealth are both necessary.

c) Tom and Pitt were the sons of uncle Austin.

2) If two nouns are joined by ‘and’ as above but if they refer to one and the same person then the verb should be singular and not plural.

a) The poet and the philosopher is dead, and not ‘are dead’.

b) The Collector and Magistrate is here, and not ‘are here’.

3) A singular noun, connected to another noun by with, together with, as well as, require a singular verb as,

a) The king with all his men, was killed, and not ‘were killed’.

b) Brad as well as Joseph likes tea, and not ‘like tea’.

4) Two or more singular nouns, separated by or, either or, neither nor take singular verb.

a) John or Jack is in the right.

b) Neither praise nor blame affects him.

5) When a collective noun indicates the opinion of each of its individuals, the verb is in plural and not in singular.

a) The jury were divided in their opinions.

b) The committee are divided on this point.

c) A number of candidates were caught copying.