Whose is a relative possessive word, used as a determiner before nouns. It can refer to people or things.
- This is the man whose house was burgled.
- I saw a girl whose beauty took my breath away.
Of which; that …of
Instead of whose, we can use of which or that …of to refer to things. The most common word order is noun + of which or that … of. Of which …+ noun is also possible.
Compare the following sentences. All of them express the same idea.
- He has written a book whose name I have forgotten.
- He has written a book the name of which I have forgotten.
- He has written a book that I have forgotten the name of.
- He has written a book of which I have forgotten the name.
Sentences with whose are rather formal. In an informal style other structures are preferred. With is a common way of expressing possessive ideas.
- I have got some friends with a house that looks over a river. (Less formal than I have got some friends whose house looks over a river.)