Grammar: B1 - ✨ Grammar Essentials: 🧩 Parts of Speech & 🏗️ Sentence Structure - Lesson 3: Defining Relative Clauses with "that" (for people/things)

Grammar: Defining Relative Clauses

B1 Lesson 18: Using 'That' for People & Things

What you will learn: By the end of this lesson, you will understand how to use 'that' as a common, flexible alternative to 'who' and 'which' in defining relative clauses.

A Flexible Alternative

We've learned to use who for people and which for things. Today, we learn about a very useful word that can often replace both in everyday, informal English: that.

For People

You can replace 'who' with 'that'.

The tour guide who helped us was great.
→ The tour guide that helped us was great.

For Things

You can replace 'which' with 'that'.

This is the bus which goes to the airport.
→ This is the bus that goes to the airport.

The Grammar Rule 📖

When to Use Who, Which, or That

Pronoun	Use For...	Formality
who	People only	Formal & Informal (Always correct)
which	Things only	Formal & Informal (Always correct)
that	People or Things	More Informal (Very common in speech)

Important Note: This rule only applies to defining relative clauses (clauses with essential information). In non-defining clauses (clauses with extra information, usually between commas), you cannot use 'that'. For example: "My friend, who lives in Phnom Penh, is a doctor." Here, you cannot replace 'who' with 'that'.

In Conversation

Listen to how 'that' is used naturally in a conversation about travel.

Srey Pov: Are you ready for our trip to Kep?

Thida: Almost! I just need to find the bag that I bought last week.

Srey Pov: Is it the blue one? Let's also call the driver that Sophea recommended.

Thida: Good idea. He's the one that knows the good seafood restaurants, right?

Practice Your Grammar 🎯

Exercise: Make it Informal

Rewrite these sentences by replacing the bold word with 'that'.

1. The artist who painted this is very talented.
   → The artist that painted this is very talented.
2. I lost the key which opens my hotel room.
   → I lost the key that opens my hotel room.
3. The student who sits next to me is from Korea.
   → The student that sits next to me is from Korea.
4. Where is the cheese which was in the fridge?
   → Where is the cheese that was in the fridge?

Your Grammar Mission ⭐

Listen for 'That'

The next time you watch an American or British movie, or listen to a song in English, pay close attention. Can you hear people using 'that' when they are talking about a person or a thing? Try to find one example of each.

Key Vocabulary

• Flexible (Adjective) | បត់បែនបាន
  Able to change or be used in different ways easily.
• Relative Pronoun (Noun) | សព្វនាមភ្ជាប់
  A word (who, which, that) that introduces a clause identifying a noun.
• Informal (Adjective) | មិនផ្លូវការ
  Used in relaxed, everyday situations with friends and family.