Page 36 - English Grammar in Use
P. 36

Unit
         12       for and since  when … ? and how long … ?




              A   We use for and since to say how long something has been happening.
                    We use for + a period of time:             We use since + the start of a period:
                         We’ve been waiting for two hours.           We’ve been waiting since 8 o’clock.


                                     for two hours                          since 8 o’clock

                        two hours ago              now              8 o’clock              now

                                      for                                       since
                     two hours    a long time  a week           8 o’clock    April        lunchtime
                     20 minutes   six months   ages             Monday       2001         we arrived
                     five days    50 years     years            12 May       Christmas    I got up
                         Sally has been working here for six         Sally has been working here since
                         months. (not since six months)              April.  (= from April until now)
                         I haven’t seen Tom for three days.          I haven’t seen Tom since Monday.




              B   We often leave out for (but not usually in negative sentences):
                         They’ve been married for ten years.    or     They’ve been married ten years.
                         They haven’t had a holiday for ten years.  (you need for)
                  You can use in instead of for in negative sentences (I haven’t … etc.):
                         They haven’t had a holiday in ten years. (= for ten years)
                  We do not use for + all … (all day / all my life etc.):
                         I’ve lived here all my life. (not for all my life)

              C   Compare when … ? (+ past simple) and how long … ? (+ present perfect):

                                           a:  When did it start raining?
                                           b:  It started raining  an hour ago / at 1 o’clock.
                                           a:  How long has it been raining?
                                           b:  It’s been raining  for an hour / since 1 o’clock.

                                           a:  When did Joe and Kate first meet?
                                                         ⎧  a long time ago.
                                           b:  They first met ⎨
                                                         ⎩  when they were at school.
                                           a:  How long have they known each other?
                                                                   ⎧  for a long time.
                                           b:  They’ve known each other ⎨
                                                                   ⎩  since they were at school.


              D   We say:     it’s     (= it is)     a long time
                            or  it’s been  (= it has been)  six months  (etc.)  since something happened

                         It’s two years since I last saw Joe.    or    It’s been two years since …
                         (= I haven’t seen Joe for two years)
                         It’s ages since we went to the cinema.    or    It’s been ages since …
                         (= We haven’t been to the cinema for ages)
                         How long is it since Mrs Hill died?    or    How long has it been since …
                         (= when did she die?)


        24            How long have you (been) … ? ➜ Unit 11
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