A compound subject consists of two or more nouns (Adam and Eve, cowboy and cowgirl), pronouns (your and I, he and she), or noun phrases (a basket of rotten eggs, a layer of dirt). Together, they form the subject of a sentence.
Two or more subjects or nouns that are combined to form a compound subject take a plural verb.
Forks and spoons have always been together during dinnertime.
Peter and Paul were two blackbirds.
Dick,Tom and Harry are triplets.
He, his dog and I are best friends.
The grandfather, the father and the son all have beards.
If the nouns that make up a compound subject are joined by or and both are singular, a singular verb is used.
His father or mother is a professor of insecticides.
Chicken soup or duck soup makes no difference to me because I like all soups.
If the nouns that make up a compound subject are singular and plural, the verb agrees with the noun nearer to it.
This is box title
His killers or killer is still at large.
A big box or smaller boxes do not matter to him for the storage.
The clock or the watch or both are not accurate; they tell different times.
Subjects can be infinitives. (An infinitive begins with to followed by the simple form of the verb.) Two infinitives joined by or and to form a subject take the singular or plural form of the verb.
To own or to manage a livestock farm involves a lot of work.
To dive and to swim are my hobbies.
Subjects can be gerunds. (Gerund is derived from a verb that ends in –ing but functions as a noun). One gerund takes a singular verb. When two gerunds are joined by the conjunction and, the verb that follows is plural.
Cycling is an enjoyable pastime.
Walking and jogginghave always been my favorite forms of exercises.
Barking at strangers and chasing cats is what my dog does most of the time.