Welcome to the World of Non-defining Relative Clauses!

Have you ever wanted to add a "side note" or some "bonus information" to a sentence without starting a new one? That is exactly what non-defining relative clauses do! Think of them like a "P.S." inside a sentence. They give us extra details that are interesting but not 100% necessary to understand who or what we are talking about.

Don't worry if this seems a bit technical at first. By the end of these notes, you will be using them like a pro to make your writing sound more sophisticated and detailed!

1. What exactly is a Non-defining Relative Clause?

A non-defining relative clause adds extra information about a person, thing, or place. The most important thing to remember is that if you remove this clause, the sentence still makes perfect sense and we still know exactly who or what is being discussed.

The "Side Salad" Analogy

Imagine you order a burger. The burger is the main sentence. The non-defining relative clause is like a side salad. It’s a nice extra, but if the waiter forgets the salad, you still have your burger, and you know exactly what you are eating!

Example:
My brother, who lives in Canada, is a doctor.
If we take out the bold part, the sentence is: My brother is a doctor. We still know who we are talking about (my brother), but we lost the "bonus" info about where he lives.

Quick Review:
- Defining Clause: Tells us which person/thing (Necessary).
- Non-defining Clause: Tells us extra info about a specific person/thing (Optional).

2. The Golden Rule: Commas are Your Best Friends!

In writing, non-defining relative clauses must be separated from the rest of the sentence by commas. These commas act like a pair of handles that let you "lift" the extra information out of the sentence.

Where do the commas go?

1. If the clause is in the middle of the sentence, put a comma before and after it.
Example: Mr. Wong, who is our class teacher, is very kind.

2. If the clause is at the end of the sentence, put a comma before it and a full stop at the end.
Example: We visited the Peak, which is a famous tourist spot in Hong Kong.

Memory Aid: The "Comma Sandwich"
Think of the extra information as the "filling" and the commas as the "bread." You need both pieces of bread to hold your extra-info sandwich together!

3. Relative Pronouns: Who, Which, and Whose

To start your non-defining relative clause, you need a relative pronoun. Here are the ones we use for junior secondary English:

  • Who: Used for people.
    Example: My best friend, who loves basketball, won the match.
  • Which: Used for things or animals.
    Example: This smartphone, which I bought yesterday, is very fast.
  • Whose: Used to show possession (belonging to someone).
    Example: Sarah, whose father is a pilot, travels a lot.
Important Warning!

In non-defining relative clauses, you CANNOT use the word "that". This is a very common mistake! Always use who or which.

Incorrect: The Big Buddha, that is on Lantau Island, is very tall.
Correct: The Big Buddha, which is on Lantau Island, is very tall.

4. Step-by-Step: How to Combine Two Sentences

When you want to make your writing smoother, you can join two simple sentences into one using a non-defining relative clause.

Step 1: Identify the two sentences.
Sentence A: Hong Kong Disneyland is very popular.
Sentence B: It opened in 2005.

Step 2: Find the common link.
The link is "Hong Kong Disneyland" and "It".

Step 3: Change the second link into a relative pronoun.
Since Disneyland is a place/thing, we use which.

Step 4: Put the "bonus info" inside commas.
Result: Hong Kong Disneyland, which opened in 2005, is very popular.

5. Common Mistakes to Avoid

Even the best students sometimes trip up on these! Here is what to watch out for:

  • Missing the second comma: Remember the "sandwich"! If you start a clause with a comma in the middle of a sentence, you must close it with another comma.
    Mistake: My dog, which is a poodle is very noisy.
    Fixed: My dog, which is a poodle, is very noisy.
  • Using "that": Only use "that" for defining clauses (the ones without commas). For our "extra info" clauses, stick to who or which.
  • Confusing "Who" and "Which": Always check if you are talking about a human or an object!

Did You Know?

Non-defining relative clauses are very common in news reports and science textbooks! They help writers give you background facts about people or experiments without making the sentences too long or repetitive. For example: "The experiment, which was conducted in the school lab, proved that air has weight."

Key Takeaways Summary

1. Extra Info: Non-defining clauses give "bonus" details that aren't strictly necessary.
2. Comma Power: Always use commas to separate the clause from the main sentence.
3. No "That": Only use who (people), which (things), or whose (possession).
4. Meaning: If you delete the clause, the sentence should still make sense!

Keep practicing! The more you use these clauses, the more professional your English essays will look!