Relative clauses

1. Defining or non-defining relative clauses?
Sometimes defining and non-defining relative clauses can look very similar but have
different meanings.
Compare
non-defining defining
His brother, who works at the
supermarket, is a friend of mine.
He has only one brother, and that
brother works at the supermarket.
His brother who works at the supermarket is a friend of
mine.
He has more than one brother. The one I’m talking about
works at the supermarket.
It’s hoped that we will raise £10,000
for local charities, which help the
homeless.
The money is intended for local
charities. All these local charities help
the homeless.
It’s hoped that we will raise £10,000 for local
charities which help the homeless.
The money is intended for local charities. Some of these
local charities help the homeless. There are other local
charities as well as these.
Warning:
The information in a defining relative clause is essential, so we can’t leave out the relative
clause. The information in a non-defining relative clause is extra information which isn’t
essential, so we can leave out the relative clause.
The man who lives next to me has five motorbikes.
In this sentence, ‘who lives to me’ is necessary. Without it, the sentence (‘The
man has five motorbikes’) is meaningless because it is not clear which man is
being talked about. Therefore, commas are NOT necessary.
Tom, who lives next to me, has five motorbikes.
In this sentence, ‘who lives to me’ is not necessary. Without it, the sentence
(‘Tom has five motorbikes’) still has meaning. ‘Who lives next to me’ adds
more information, therefore, commas ARE necessary.
Common Mistakes
Some Students do not put the non defining relative clause close to the noun it
describes.
The chemicals flow into rivers, which are toxic. => The chemicals, which are
toxic, flow into rivers.