Grammar: B2 section "✨ Grammar Essentials: 🧩 Parts of Speech & 🏗️ Sentence Structure (Advanced)" is: L1: Non-Defining Relative Clauses (using who, which, with commas)

Grammar: Relative Clauses

B1 Lesson 1: Non-Defining Relative Clauses

What you will learn: By the end of this lesson, you will be able to use non-defining relative clauses with correct punctuation and pronouns (who, which) to add extra information to your sentences.

Why It Matters: The Power of the Comma

A non-defining relative clause gives extra, "bonus" information about a noun. Using commas completely changes the meaning of the sentence.

Defining Clause (No Commas)

My sister who lives in Battambang is a doctor.

This gives essential information. It means I have more than one sister, and I am identifying which one I'm talking about.

Non-Defining Clause (With Commas)

My sister, who lives in Battambang, is a doctor.

This gives extra information. It means I have only one sister. We already know who she is; her location is just a bonus fact.

The Grammar Rules 📖

There are two very important rules for non-defining clauses.

Rules for Non-Defining Clauses

1. You MUST use commas to separate the clause from the rest of the sentence.
2. You CANNOT use the relative pronoun 'that'. You must use 'who' for people and 'which' for things.

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Examples:

• People (who): "Mr. Dara, who is my favorite teacher, is very kind."
• Things (which): "The Bamboo Train, which is a famous attraction, is very popular."
• Places (where): "Battambang, where I grew up, is a beautiful city."
• Possession (whose): "My friend Lina, whose brother is a famous singer, invited me to a concert."

💡 Pro Tip: Sounding More Sophisticated

Non-defining clauses are very common in formal and academic writing. Using them correctly makes your writing sound more advanced and allows you to combine ideas smoothly, avoiding short, choppy sentences.

Practice Your Grammar 🎯

Exercise 1: Punctuation & Pronouns

1. Which sentence is grammatically correct?
   a) My car, that is blue, is parked outside.
   b) My car, which is blue, is parked outside.
   → Answer: b. (We must use 'which' for things in non-defining clauses, not 'that'.)
2. Combine these sentences: "Angkor Wat is a world-famous temple. It is located in Siem Reap."
   → Answer: Angkor Wat, which is located in Siem Reap, is a world-famous temple.
3. The man _______ lives next door to me is from France. (who / , who,)
   → Answer: who. (This is a defining clause because it tells us *which* man. No commas.)
4. My oldest brother, _______ works as an engineer, lives in Phnom Penh. (who / that)
   → Answer: who. (This is non-defining because "my oldest brother" is specific. We cannot use 'that'.)

Your Grammar Mission ⭐

Writing Task: Combine the Sentences

Combine the sentences using a non-defining relative clause. Remember your commas!

1. My favorite cafe is Kinyei Cafe. It is located near the river in Battambang.
   → My favorite cafe is Kinyei Cafe, which is located near the river in Battambang.
2. My best friend is named Sam. He is very good at playing the guitar.
   → My best friend, who is very good at playing the guitar, is named Sam.

Key Vocabulary

• Non-Defining Relative Clause (Noun)
  A clause that gives extra, non-essential information about a noun that is already specific. It is separated by commas.
• Defining Relative Clause (Noun)
  A clause that gives essential information to identify which person or thing we are talking about. It does not use commas.
• Essential (Adjective) | ចាំបាច់
  Absolutely necessary; extremely important.