219. Pronouns are very agreeable members of the co-operative commonwealth of words. They strive to agree with their antecedents. Sometimes we do not allow the pronoun to agree, and then our sentence is incorrect.
A pronoun must agree with its antecedent in number, gender and person.
For example, if you are referring to one man, you must use a masculine pronoun, singular, third person form, as I saw the man but he did not see me. Man is the antecedent. It is singular, masculine, third person and so we use the pronoun he.
The girl came, but she could not stay. In this sentence girl is the antecedent; it is singular, feminine, third person, and so we use the pronoun she.
The boys did not come when the teacher called them. In this sentence boys is the antecedent; it is plural, masculine, third person, and so we use the pronoun them.
220. Sometimes there are two words used as the antecedent, joined by and. We use a singular pronoun in referring to them if they denote the same person or thing; as:
- The secretary and treasurer (one person) resigned his position.
- My comrade and friend (one person) gave me his help.
221. But two nouns joined by and, that mean different persons or things, must be represented by a plural pronoun, thus:
- Marx and Engels (two persons) wrote their call to liberty, the Communist-Manifesto.
- Men and women will struggle for their freedom.
- Childhood and youth should have their rightful joys.
222. Use the singular pronoun when the nouns are kept separate by the use of each, every, many a, or no.