1. What are Relative Pronouns?
   Relative pronouns connect a dependent (relative) clause to a main clause and provide more information about a noun. They help to combine sentences or clarify details about people, places, things, or ideas.

---

2. ‘Who’

• ‘Who’ is used when referring to people and serves as the subject of a relative clause. Examples:
• The student who won the competition is my friend.
• She is the person who helped me.
  (In these examples, ‘who’ performs the action in the relative clause: ‘won’ and ‘helped’.)

---

3. ‘Whom’

• ‘Whom’ is used when referring to people and serves as the object of a verb or preposition in a relative clause. Examples:
• The professor whom I emailed replied quickly.
• The person whom the police arrested is innocent.
  (In these examples, ‘whom’ receives the action: ’emailed’ and ‘arrested’.)
• Tip: To decide between ‘who’ and ‘whom’, use he/she for ‘who’ and him/her for ‘whom’.
• Example: He emailed → who; I emailed him → whom.

---

4. ‘Whose’

• ‘Whose’ shows possession and can refer to both people and things. Examples:
• The girl whose book was lost is upset.
• This is the house whose roof was damaged by the storm.
  (In these sentences, ‘whose’ shows who owns the book and the roof.)

---

5. ‘Which’

• ‘Which’ is used to refer to things, animals, or ideas and provides additional information. It introduces non-essential clauses that can be left out without changing the main meaning of the sentence. These clauses are often separated by commas. Examples:
• The book, which is on the table, is mine.
• The movie, which was very long, received mixed reviews.
  (In both sentences, ‘which’ refers to non-essential details.)

---

6. ‘That’

• ‘That’ refers to people, things, animals, or ideas and introduces essential clauses. These clauses cannot be omitted without altering the meaning of the sentence. Unlike ‘which’, the clause starting with ‘that’ is crucial to the meaning. Examples:
• The car that I bought is red.
• This is the team that won the championship.
  (In these examples, ‘that’ introduces information vital to the sentence’s meaning.)

---

7. ‘Which’ vs. ‘That’

• Use ‘which’ for non-essential information (use commas).
• Example: The painting, which is in the living room, is beautiful. (We can remove the clause, and the sentence still makes sense.)
• Use ‘that’ for essential information (no commas).
• Example: The painting that is in the living room is beautiful. (We need the clause to know which painting is being discussed.)

---

8. Relative Clauses
   There are two types of relative clauses:

• Restrictive (essential) clauses: Give necessary information about the noun.
  • Example: The student who passed the test is here. (Identifies which student.)
• Non-restrictive (non-essential) clauses: Add extra, non-essential information.
  • Example: My brother, who lives in New York, is visiting. (‘Who lives in New York’ gives extra info, but isn’t essential to identify the brother.)

---

9. Common Errors with Relative Pronouns

• Using ‘who’ instead of ‘whom’ when the pronoun is an object.
• Incorrect: The person who I met was kind.
• Correct: The person whom I met was kind. (Whom is the object of ‘met’.)
• Using ‘which’ when ‘that’ is needed.
• Incorrect: The book which I read was interesting.
• Correct: The book that I read was interesting. (‘That’ is used for essential information.)

---

10. Quick Reference for Relative Pronouns

• Who: Refers to people (as a subject).
• Whom: Refers to people (as an object).
• Whose: Shows possession (for people or things).
• Which: Refers to things or ideas (for non-essential clauses).
• That: Refers to people, things, or ideas (for essential clauses).

---