I. Introduction: Understanding "Who" and "Which"

a. Defining "who" (referring to people)
b. Defining "which" (referring to things and animals)
c. Basic sentence structures with "who" and "which"

II. Practice Exercises: 23 Questions Using "Who" and "Which"
a. Questions 1-7: Simple sentences focusing on identifying people.
b. Questions 8-14: Sentences involving possessive pronouns and descriptive phrases.
c. Questions 15-21: Sentences with more complex structures and embedded clauses.
d. Questions 22-23: Challenge questions requiring deeper understanding.

III. Answer Key and Explanations
a. Detailed explanations for each question, clarifying the correct usage of "who" and "which."
b. Highlighting common mistakes and providing guidance for future usage.

Understanding "Who" and "Which"

The relative pronouns "who" and "which" are essential parts of English grammar, used to add extra information about a noun in a sentence. They introduce relative clauses, which provide further detail. The key difference lies in what they refer to:

• Who: "Who" is used to refer to people. It acts as the subject or object within the relative clause. For example: "The boy who won the race is very happy." Here, "who won the race" adds information about the boy.

• Which: "Which" is used to refer to things and animals. It also acts as the subject or object within the relative clause. For example: "The car which I bought is very reliable." Here, "which I bought" adds information about the car.

Understanding the distinction between "who" and "which" is crucial for constructing grammatically correct and clear sentences. The basic structure for sentences using these relative pronouns generally follows this pattern: [Noun] + [Relative Pronoun] + [Relative Clause].

Practice Exercises: 23 Questions Using "Who" and "Which"

Here are 23 questions designed to test your understanding of "who" and "which." Choose the correct relative pronoun to complete each sentence.

Simple Sentences:

1. The girl ___ won the spelling bee is my best friend. (who / which)
2. The dog ___ barked all night is very noisy. (who / which)
3. The teacher ___ teaches math is very kind. (who / which)
4. The book ___ I borrowed is very interesting. (who / which)
5. The bird ___ sang beautifully is a robin. (who / which)
6. The boy ___ broke the window is in trouble. (who / which)
7. The artist ___ painted the mural is famous. (who / which)

Sentences with Possessive Pronouns and Descriptive Phrases:

8. The student ___ project won an award is very talented. (whose / which)
9. The house ___ roof is red is very old. (whose / which)
10. The cat ___ fur is black is sleeping. (whose / which)
11. The musician ___ songs are popular is performing tonight. (whose / which)
12. The tree ___ branches are long is very tall. (whose / which)
13. The car ___ engine is noisy needs repair. (whose / which)
14. The girl ___ backpack is blue is my sister. (whose / which)

More Complex Sentences:

15. The restaurant, ___ we ate last night, serves delicious food. (where / which)
16. The city, ___ I visited last summer, is beautiful. (which / who)
17. The reason, ___ he left, is still unclear. (why / which)
18. The story, ___ the teacher read, was very exciting. (that / which)
19. The reason ___ I am late is because of the traffic. (which / why)
20. The book, ___ cover is blue, is mine. (whose / which)
21. The painting, ___ he bought at auction, is a masterpiece. (which / who)

Challenge Questions:

22. The scientist, ___ groundbreaking research earned her a Nobel Prize, dedicated her life to finding a cure for cancer. (whose / who)
23. The old oak tree, ___ massive branches stretched across the entire park, provided shade for many generations. (whose / which)

Answer Key and Explanations

1. who: "Who" refers to the girl.
2. which: "Which" refers to the dog.
3. who: "Who" refers to the teacher.
4. which: "Which" refers to the book.
5. which: "Which" refers to the bird.
6. who: "Who" refers to the boy.
7. who: "Who" refers to the artist.
8. whose: "Whose" shows possession, referring to the student’s project.
9. whose: "Whose" shows possession, referring to the house’s roof.
10. whose: "Whose" shows possession, referring to the cat’s fur.
11. whose: "Whose" shows possession, referring to the musician’s songs.
12. whose: "Whose" shows possession, referring to the tree’s branches.
13. whose: "Whose" shows possession, referring to the car’s engine.
14. whose: "Whose" shows possession, referring to the girl’s backpack.
15. which: "Which" refers to the restaurant.
16. which: "Which" refers to the city.
17. why: "Why" refers to the reason. Note that "which" would be grammatically incorrect here.
18. which: "Which" refers to the story.
19. why: "Why" refers to the reason. "Which" is incorrect in this context.
20. whose: "Whose" shows possession, referring to the book’s cover.
21. which: "Which" refers to the painting.
22. whose: "Whose" shows possession, referring to the scientist’s research.
23. whose: "Whose" shows possession, referring to the tree’s branches.

These exercises illustrate the subtle but important differences between "who" and "which," and how these pronouns are used to create more descriptive and informative sentences. By practicing these types of questions, students can develop a stronger understanding of relative clauses and improve their overall English grammar skills. Remember to pay close attention to what the pronoun is referring to – a person, or a thing/animal – to ensure correct usage. Consistent practice is key to mastering this aspect of English grammar.