Some nouns that call groups can be either singular or plural depending on their meaning in individual sentences. It can be unclear whether collective and innumerable nouns should be treated as a singular or a plural. The rules of the agreement do not apply to has-haves when used as a second ancillary contract in a couple. Some nouns are regularly plural in form, but singular in meaning. Exception: If the two nouns do not refer to separate things, but to a single entity, use a singular verb. People are often confused when deciding whether a singular or plural verb should correspond to certain collective nouns.