1. Relative Pronouns
& clauses

2. The person who phoned me last night is my teacher.
A relative pronouns is a type of pronoun that often introduces dependent (or relative) clauses in sentences. They also can stand alone as the subject or object of a sentence.
There is a specific list of relative pronouns, and here they are: who, whoever, whom, that, which, when, where, and whose. (what, which, and where can also serve as relative pronouns.)
Example:
The person who phoned me last night is my teacher.
In the above example, "who": relates the clause "A person phoned me last night ", to the clause " The person is my teacher "

3. There are five relative pronouns: who, whom, whose, which, that
- The person who phoned me last night is my teacher. - The person that phoned me last night is my teacher.
- The car which hit me was yellow. - The car that hit me was yellow.
- The person whom I phoned last night is my teacher. - The people who I phoned last night are my teachers. - The person that I phoned last night is my teacher. - The person I phoned last night is my teacher.
- The car which I drive is old. - The car that I drive is old. - The car I drive is old.
- The student whose phone just rang should stand up. - Students whose parents are wealthy pay extra.
- The police are looking for the car whose driver was masked. - The police are looking for the car of which the driver was masked.