Non-restrictive clauses provide information that does not change the meaning of the sentence if it is removed.
These clauses are introduced by who (for humans) and which (for animals and things).
Example: The desk, which is made of faux-wood, is heavier than I expected. (You could say: The desk is heavier than I expected.)
Example: Bernice, who studies archaeology, is going to Greece this summer. (You could say: Bernice is going to Greece this summer.)
In the middle of a sentence, non-restrictive clauses are surrounded by commas, and at the end of a sentence they are preceded by a comma.
Restrictive clauses provide information that is essential to the meaning of the sentence.
These clauses are introduced by who (for humans) and that (for humans, animals, and things).
Example: Fruit that is organic is more expensive than non-organic fruit. (You can’t say: Fruit is more expensive than non-organic fruit.)
Example: The man who bought my car owns a record shop. (You can’t say: The man owns a record shop.)
Example: The man that bought my car owns a record shop. (“That” and “who” can both be used with humans.)
Restrictive clauses do not use commas.
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