👈 Just arriving? Start at the beginning: Part 1: Who, Which & That | Part 2: Defining vs. Non-Defining & Omitting Pronouns
⏭️ Already know the theory? Go straight to the full quiz!
You've mastered the core relative pronouns and the defining/non-defining distinction. Now let's go further — prepositions, "what," quantifiers, all the common mistakes, and a full set of practice exercises. Let's finish strong! 🚀
Prepositions in Relative Clauses
In formal English, prepositions can go before "which" or "whom." In informal English, they go at the end — which is how most people actually speak.
Formal (preposition before):
- The hotel in which we stayed was excellent.
- The woman to whom I spoke was very helpful.
- The issue about which we're concerned is serious.
Informal (preposition at the end):
- The hotel which we stayed in was excellent.
- The hotel we stayed in was excellent. ✅ (most natural)
- The woman I spoke to was helpful. ✅
Important: You cannot use "that" directly after a preposition:
- ❌ The hotel in that we stayed...
- ✅ The hotel in which we stayed... (formal)
- ✅ The hotel that we stayed in... (informal)
WHAT — A Special Case
"What" means "the thing(s) that" — and unlike other relative pronouns, it doesn't need a noun before it.
- What you need is a vacation. (= The thing that you need)
- I don't understand what he said. (= the thing that he said)
- What happened was surprising. (= The thing that happened)
Compare: What I bought was expensive. = The thing that I bought was expensive. (same meaning)
Quantifiers with Relative Clauses
We can use quantifiers (all, some, many, none, etc.) before "of which" or "of whom." This is a more advanced structure but very useful.
- I have three brothers, all of whom are doctors.
- She has ten books, some of which are very old.
- I invited twenty people, none of whom came.
- There were 50 students, many of whom passed the exam.
Pattern: noun + comma + quantifier + of which/whom + verb
Quick Reference: Advanced Structures
| Structure | Use | Example |
|---|---|---|
| Preposition + which/whom | Formal writing | The hotel in which we stayed... |
| which/that + preposition at end | Informal / spoken | The hotel we stayed in... |
| what | "The thing(s) that" — no noun needed before it | What you need is rest. |
| quantifier + of which/whom | Referring to part of a group | ...twenty guests, none of whom came. |
Common Mistakes — The Full List
❌ Mistake 1: Forgetting commas in non-defining clauses
- ❌ My sister who lives in Paris is a doctor. (suggests I have more than one sister)
- ✅ My sister, who lives in Paris, is a doctor.
❌ Mistake 2: Using "that" in non-defining clauses
- ❌ My sister, that lives in Paris, is a doctor.
- ✅ My sister, who lives in Paris, is a doctor.
❌ Mistake 3: Using "what" instead of "that"
- ❌ The book what I read was good.
- ✅ The book that I read was good.
❌ Mistake 4: Omitting subject pronouns
- ❌ The man called you is waiting.
- ✅ The man who called you is waiting. (subject — must keep!)
❌ Mistake 5: Wrong relative pronoun
- ❌ The woman which I met was nice.
- ✅ The woman who I met was nice.
❌ Mistake 6: Double subject
- ❌ The man who he lives next door is friendly.
- ✅ The man who lives next door is friendly.
❌ Mistake 7: "That" after a preposition
- ❌ The hotel in that we stayed was excellent.
- ✅ The hotel in which we stayed was excellent. (formal)
- ✅ The hotel that we stayed in was excellent. (informal)
Practice Exercises
Time to put it all together! Work through these, then check your answers below. No peeking! 👀
Exercise 1: Formal or informal? Rewrite in the other style.
- Formal: The hotel in which we stayed was excellent. → Informal: _______
- Informal: The woman I spoke to was helpful. → Formal: _______
Exercise 2: Spot and correct all the mistakes.
- The woman which I met was nice.
- My sister, that lives in Paris, is a doctor.
- The man called you is waiting.
- The book what I read was good.
- The hotel in that we stayed was excellent.
- My sister who lives in Paris is a doctor. [I have one sister]
Exercise 3: Fill in the gap — what, quantifier + of which/whom.
- I don't understand _______ he said.
- She bought five dresses, _______ were on sale.
- I invited thirty people, _______ came.
- _______ you need is more practice.
Exercise 4: Define or non-define? Add commas where needed.
- People who exercise regularly are healthier. [which people? — defining]
- John who is my best friend got married last year. [we know who John is]
Answers
Exercise 1
- The hotel we stayed in was excellent. (or: The hotel that we stayed in was excellent.)
- The woman to whom I spoke was helpful.
Exercise 2
- The woman who I met was nice.
- My sister, who lives in Paris, is a doctor.
- The man who called you is waiting.
- The book that I read was good.
- The hotel in which we stayed was excellent. / The hotel that we stayed in...
- My sister, who lives in Paris, is a doctor. (commas needed — one sister)
Exercise 3
- what
- some of which
- none of whom
- What
Exercise 4
- People who exercise regularly are healthier. (no commas — defining)
- John, who is my best friend, got married last year. (commas needed)
How did you do? If you're feeling solid, the full interactive quiz below is the perfect final test. If a few answers surprised you, go back and re-read the relevant section in Part 2 before you try it — you'll do much better! 💪
🎯 Take the full interactive Relative Clauses quiz!
👈 Part 1: Who, Which & That | Part 2: Defining vs. Non-Defining & Omitting Pronouns
Part of the LearnFast.life Grammar Series
