1. Defining and Non-Defining Adjective Clauses LEVEL 500

2. Which is used for things.
A Defining Adjective Clause is a necessary part of a sentence, as it defines which noun the speaker is referring to.
Who is used for people.
Which is used for things.
That is used for animals, people, and things.

3. Which is used for things. That is never used.
A Non-Defining Adjective Clause is extra information in a sentence. It is not necessary for the meaning of the sentence.
who is used for people.
Which is used for things.
That is never used.

4. The man who sat down was Mike. (Defining Adjective Clause)
Examples
The man who sat down was Mike. (Defining Adjective Clause)
(In this sentence, you can't omit "who sat down." It is defining which man.)

5. Examples
The man, who I had never met before, was looking at me strangely. (Non-Defining Adjective Clause)
(In this sentence, you can omit "who I had never met before." It is simply extra information.)

6. Non-Defining Adjective Clauses give us secondary (I. E
Non-Defining Adjective Clauses give us secondary (I.E. extra) information about a person or thing.

7. Examples
My friend John, who is from Canada, loves to play football.
The report, which is on the table, was completed yesterday.

8. Defining Adjective Clauses are more common in spoken English.
Non-Defining Adjective Clauses are more formal and common in writing.
In speaking, we usually say two sentences instead of one sentence with a Non-Defining Relative Clause.

9. Examples
My friend John loves to play football. He's from Canada. (Spoken)
My friend John, who is from Canada, loves to play football. (Written)

10. In Non-Defining Adjective Clauses, we use commas.
If we say these when speaking, the commas represent a pause in our speech.

11. Examples
The computer, (pause) which I bought yesterday, (pause) cost me over $2000.
David, (pause) who is sitting over there, (pause) works as a technician.