Hello, fellas. How is it going in the end of September? Our session today is about impersonal pronouns.
According to Betty Schrampfer Azar, a pronoun refers to a noun. The noun it replaces is called the antecedent. Based on their antecedents, pronouns are divided into two categories: singular pronouns and plural pronouns. A singular pronoun refers to a singular noun. On the other hand, the antecedent of a plural pronoun is a plural noun.
Sometimes, pronouns are used to refer to no antecedent. They are called impersonal pronouns. There are three impersonal pronouns: you, one, and they. You and one carry the same meaning as they refer to “any person, people in general”. However, you is less formal than one and more common in everyday English.
1) You should pay to attention to the announcement. (informal)
2) One should pay to attention to the announcement. (formal)
As an impersonal pronoun, they means “some people or somebody” in spoken English. However, the antecedent is implied or not stated.
Why did Ann lose her job?
They fired her.
On the sentence above, they refers to the people for whom Ann worked.
Betty Schrampfer Azar, Understanding and Using English Grammar: Third Edition