Agreement of personal pronouns with their antecedents

Agreement of personal pronouns with their antecedents
The pronoun I is used to refer to the speaker or writer. The pronoun you is used to refer to one or more persons or things which are being addressed by the speaker or writer. The pronoun we is normally used to refer to the speaker or writer together with one or more other people.

When a pronoun stands for a noun which has already been mentioned, the noun is sometimes referred to as the antecedent of the pronoun.
e.g. The apples are cheap, but they are not ripe yet.
In the preceding example, the noun apples is the antecedent of the pronoun they.

The antecedents of pronouns usually precede the pronouns. However, a pronoun may also stand for a noun which follows the pronoun, provided that it is obvious to what the pronoun is referring.
e.g. Because they are sour, the apples will be used for cooking.
In this example, the pronoun they stands for the noun apples, which occurs later In the sentence.

a. Male and female antecedents
The third person singular pronouns he and she are the only pronouns in the subjective case which are differentiated with respect to gender. The pronoun he is used to refer to male antecedents, and the pronoun she is used to refer to female antecedents.
e.g. A girl was sitting on the steps. She was waiting for her friend.
A boy was delivering papers. He seemed to be in a hurry.
In the above examples, the pronoun she agrees with the female antecedent girl, and the pronoun he agrees with the male antecedent boy.

b. Singular and plural antecedents
English third person pronouns are also differentiated with respect to number. If the antecedent of a pronoun is singular, a singular pronoun must be used. If the antecedent of a pronoun is plural, a plural pronoun must be used.
e.g. I have one watch. It is quite accurate.
I have two watches. They are quite accurate.

This is my sister. She is younger than I am.
These are my sisters. They are younger than I am.

This is my brother. He is older than I am.
These are my brothers. They are older than I am.

In the above examples, the singular pronouns it, he and she agree with the singular antecedents watch, sister and brother. The plural pronoun they agrees with the plural antecedents watches, sisters and brothers.

As illustrated above, the third person plural pronoun they can be used to stand for either male or female antecedents.
e.g. The men liked to play cards. They took turns keeping score.
The women came, but they did not stay long.
The men and women greeted each other. They all knew one another.