Page 511 - Practical English Usage 3ed - Michael Swan, Oxford

relatives (2): identifying and non-identifying clauses 495
8 whose: a girl whose hair . ..
Whose is a possessive relative pronoun, used as a determiner before nouns. It replaces his!herlits. For more details, see 496.
I saw a girl whose hair came down to her waist. (NOT •.. !tJh6~ he, hair eame tfflftln ...)
9 which referring to a whole clause
Which can refer not only to a noun, but also to the whole of a previous clause. Note that what cannot be used in this way.
He got married again a year later, which surprised everybody. (NOT .•• , what sttrprisetl everyhtJdy.)
ShecycledfromLondontoGlasgow, whichisprettygoodforawomanof75. (NOT She cycled ... , what is pretty gB6d ...)
10 relative when, where and why
When and where can introduce relative clauses after nouns referring to time and place. They are used in the same way as preposition + which.
I'll never forget the day when I first met you. (= ..• the day on which ...)
Do you know a shop where I can find sandals? (= ••• a shop at which ...) Why is used in a similar way after reason.
Do you know the reason why she doesn't like me? (= ..• the reason for which ...)
495 relatives (2):
identifying and non-identifying clauses
1 two kinds of relative clause
Some relative clauses identify or classify nouns: they tell us which person or thing, or which kind of person or thing, is meant. (In grammars, these are called 'identifying', 'defining' or 'restrictive' relative clauses.)
What's the name ofthe tall man who just came in? People who take physical exercise live longer.
Who owns the car which is parked outside?
Have you got something that will get ink out ofa carpet?
Other relative clauses do not identify or classify; they simply tell us more about a person or thing that is already identified. (In grammars, these are called 'non-identifying', 'non-defining' or 'non-restrictive' relative clauses.)
This is Ms Rogers, who's joining the firm next week.
In 1908 Ford developed his Model T car, which sold for $500.
There are several grammatical differences between the two kinds of relative clause. There are also stylistic differences: non-identifying clauses are generally more formal, and are less frequent in informal speech.
2 pronunciation and punctuation
Identifying relative clauses usually follow immediately after the nouns that they modify, without a break: they are not separated by pauses or intonation movements in speech, or by commas in writing. Cfhis is because the noun would be incomplete without the relative clause, and the sentence would •
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