Who, which, and whose are all relative pronouns, which means they are used to introduce relative clauses. A relative clause is a group of words that contains a subject and a verb and modifies a noun or pronoun. Who, which, and whose can be used to introduce a relative clause that modifies a noun or pronoun.
Who
Who is used to introduce a relative clause that modifies a human noun or pronoun. For example,
The woman who is standing next to the car is my sister.
In this sentence, the relative clause who is standing next to the car modifies the woman. The woman is the subject of the relative clause, and is standing is the verb. We can also use who with the subject pronoun she, as in the following sentence.
She is the woman who is standing next to the car.
Which
Which is used to introduce a relative clause that modifies a non-human noun or pronoun. For example,
The car which is parked in the driveway is my sister’s.
In this sentence, the relative clause which is parked in the driveway modifies the car. The car is the subject of the relative clause, and is parked is the verb. We can also use which with the subject pronoun it, as in the following sentence.
It is the car which is parked in the driveway.
Whose
Whose is used to introduce a relative clause that modifies a noun or pronoun with possession. For example,
The woman whose car is parked in the driveway is my sister.
In this sentence, the relative clause whose car is parked in the driveway modifies the woman. The woman is the subject of the relative clause, and is parked is the verb. We can also use whose with the subject pronoun she, as in the following sentence.
She is the woman whose car is parked in the driveway.
