Defining and non-defining relative clauses explained

Defining and non-defining relative clauses explained. There are two common types of relative clause:

  1. Defining relative clauses (also called ‘restricting relative clauses’ or ‘identifying relative clauses’)
  2. Non-defining relative clauses (also called ‘non-restricting relative clauses’ or ‘non-identifying relative clauses’)

1. Defining relative clauses

A defining relative clause is one in which the clause is required for the understanding / grammar of the sentence. Here’s an example:

  • She is the teacher who helped me with my homework.
  • The shoes which I bought on Saturday are very comfortable.

If we remove the relative clause ‘who helped me with my homework‘, we are left with ‘She is the teacher’ which (without any other context) does not make a clear point. She is the teacher that…what? It doesn’t stand alone as a logical statement.

In the second example, if we remove the relative clause ‘which I bought on Saturday’, we are left with the ‘The shoes are very comfortable’. Again, without any extra context, this is not a clear point. What shoes? Again, it doesn’t stand alone as a logical statement.

With defining relative clauses, we can change the question word for ‘that’:

  • She is the teacher that helped me with my homework.
  • The shoes that I bought on Saturday are very comfortable.

2. Non-defining relative clauses

A non-defining relative clause is one in which the clause is NOT required for the understanding / grammar of the sentence. A non-defining relative clause adds extra information, but we can remove it and the sentence will still make sense.

Example:

  • My friend, who comes from Australia, loves surfing.
  • These shoes, which I bought on Saturday, are very comfortable.

In the first example, if we remove the relative clause ‘who comes from Australia‘, we are left with ‘My friend loves surfing.’ Even without the information about Australia, this is still a logical and clear sentence.

In the second example, if we remove the relative clause ‘which I bought on Saturday‘, we are left with ‘These shoes are very comfortable’. Even without the information about when you bought them, this is still a logical and clear sentence.

NOTE: In non-defining relative clauses, we CANNOT change the question word for ‘that’.

  • My friend, who comes from Australia, loves surfing.
  • My friend, that comes from Australia, loves surfing.
  • These shoes, which I bought on Saturday, are very comfortable.
  • These shoes, that I bought on Saturday, are very comfortable

In addition to not using ‘that’, non-defining relative clauses differ from defining relative clauses in that they use commas to show that the clause is not essential to the grammar of the sentence. Defining relative clauses do not use commas.

DEFINING RELATIVE CLAUSES – NO COMMAS

  • She is the teacher that helped me with my homework.
  • The shoes that I bought on Saturday are very comfortable.
  • She is the teacher who helped me with my homework.
  • The shoes which I bought on Saturday are very comfortable.

NON-DEFINING RELATIVE CLAUSES – WITH COMMAS

  • My friend, who comes from Australia, loves surfing.
  • These shoes, which I bought on Saturday, are very comfortable.

 

Using expressions of amount with non-defining relative clauses

Non-defining relative clauses can also be introduced using an expression showing amount before the relative pronoun. Here are some the expressions that can be used:

all of, some of, any of, a few of, each of, both of, either of, half of, most of, many of, much of, none of, one of, two of, (and so on).

Here are some examples:

  • My friends, both of whom come from Australia, love surfing.
  • The shopping, most of which is still in the car, was very expensive.
  • She told us about her new friend, which none of us knew anything about.