Relative clauses: where, when, whose & prepositions

Rules

• Rule 1: where or which?

  After a place, use where when the clause is already complete (the verb has its object or needs none). If the verb needs the place as its object (visit, see, like), use which / that.

  Example: the park where we played soccer

  Example: the park which we visited

• Rule 2: when and why

  After time nouns (day, year, moment), use when. After the reason, use why (or that).

  Example: I remember the day when we got our puppy.

  Example: That's the reason why I'm smiling.

• Rule 3: whose = possession

  whose + noun shows that something belongs to someone or something. It works for people, animals and things. Don't confuse it with who's (= who is)!

  Pattern: noun + whose + noun + verb

  Example: a boy whose bike is green

  Example: a book whose cover is torn

• Rule 4: where does the preposition go?

  In formal English, the preposition comes first: in which, to whom. In everyday English, it goes at the end: the room (that) I sleep in. Never both! Don't use that or who right after a preposition.

  Pattern: formal: preposition + which / whom · informal: … + preposition

  Example: the room in which I sleep

  Example: the room I sleep in

Common mistakes

• the museum where we visited → the museum which we visited

  visit needs an object → which / that.

• the house in which I live in → the house in which I live

  Use the preposition once: at the start or at the end.

• the girl who's mother is a doctor → the girl whose mother is a doctor

  Possession → whose; who's = who is.