Defining Relative Clauses
Take a look at the following sentences:
1) “That is the castle where they filmed ‘Harry Potter’
2) “Henry loves dogs that wag their tails”
Here, both 1) and 2) use defining clauses to provide important information about the objects in each sentence. In the first example, ‘where’, tells us about ‘the castle’ we are talking about. In the second, ‘that’, tells us about the kind of dogs Henry is interested in.
However, without the information provided in these clauses, our overall understanding of each sentence would remain unclear.
* “That is the castle” Which castle?
* “Henry loves dogs” What kind of dogs?
So, defining relative clauses include information that is essential to understanding a sentence. Without these clauses, the sentence does not make total sense.
Non-Defining Relative Clauses
Now, lets compare the examples above with three new sentences:
3) “Anders, who was tall and fashionable, enjoyed chatting to women”
4) “The London Underground, which is always crowded, is a terrible form of transportation”
5) “Manchester United, who had recently won the English Premier League, were scheduled to play Chelsea on Saturday.
The sentences above provide us with a different kind of information to that found in 1) and 2). Here, the use of non-defining relative clauses give us extra information , that is not essential to understanding a sentence.
In sentence 3), the essential information is that Anders enjoys talking to women. He may be tall and fashionable, but these are just extra, descriptive adjectives about his appearance. So, the ‘who’ clause does not define our subject nor our object.
In sentence 4), we read an opinion about the London Underground (the opinion that it is ‘terrible’). Although it may be crowded and extremely uncomfortable to ride on, this ‘which’ clause simply provides additional information about why it might be terrible and is not essential to the sentence’s overall meaning.
Finally, in sentence 5), Manchester United could be the best or worst soccer team in the world. However, this information is not important. Whatever players they might have, they must still play Chelsea on Saturday.
There we have it! A quick lesson on Defining vs. Non-Defining Relative Clauses.
Remember, punctuation is important when writing in any language. It tells the examiner that we are choosing our language carefully and that we are fully aware of its purpose. Always be sure to place a ‘comma’ in front of any relative pronoun (who, which, that, where etc. ) and at the very end of a clause, before the sentence’s essential information.