before (conjunction)

    [clause + before + clause
    before + clause, + clause]
  • We can use before to join two clauses.
    We can either say: A happened before B happened
      OR Before B happened, A happened.

    The meaning is the same: A happened first.
    Note the comma (,) in the second structure.

      I bought a lot of new clothes before I went to America.
      Before! went to America, I bought a lot of new clothes.
      He did military service before he went to university.
      ( = He did military service first.)
      Before he did military service, he went to university.
      ( = He went to university first.)
  • In a clause with before, we use a present tense if the meaning is future.
      I ‘ll telephone you before you leave.(NOT before you will leave.)
  • In a formal style, we often use the structure before + -ing.
      Please put out all lights before leaving the office.
      Before beginning the book, he spent five years on research.