Dave's ESL Cafe's Student Discussion Forums

[Candles]

Dear teachers,

Sometimes I get confused with the meaning of the defining clause vs. The meaning of the non-defining clause:

Defining clause:
The man who robbed you has been arrested.
Non-defining clause:
The man, who robbed you, has been arrested.

What is the difference in meaning? Thank you.

The following can be explained because the subject is plural:
Non-defining
The students, who had revised hard, passed the exam. (All the students revised and they all passed the exam.

Defining
The students who had revised hard passed the exam. (Only some of the students revised, and these were the ones who passed the exam.)
_________________
There's life, there's hope!

[redset]

Defining clauses give information that you need to identify what thing somebody is talking about (or the kind of thing):

The man has been arrested (Which man?)
The man who robbed you has been arrested (Now you know which man I'm talking about.)

The students passed the exam (All of them passed?)
The students who had revised hard passed the exam (We're only talking about a specific group of students.)

People who exercise live longer (This specific kind of person.)


Non-defining clauses aren't necessary to understand who we're talking about, they just add some extra information:

Anders has been arrested (You know who Anders is.)
Anders, who robbed you, has been arrested (This points out that Anders robbed you at some point. You probably already knew this information, so it could be for emphasis - "You know Anders, right? The guy who robbed you?")

The students passed the exam (All of the students passed.)
The students, who had revised hard, passed the exam (This is telling you that they passed, and also letting you know that they studied hard.)

Cars, which are a form of transport, are expensive. (You could remove this useless bit of extra information and people would still know what you're talking about.)


So non-defining clauses are simply extra information, a kind of 'by the way' interjection. That's also why they appear between commas, they indicate a pause in speech and non-defining clauses are where you interrupt what you're saying to add some unnecessary information.

"You ate all my cookies - which took me all day to make, by the way - and you didn't even say thank you!"