for, since, from, ago and before

  • For, since and from ‘point forwards’ in time. Ago and before ‘point backwards’ in time.
    THEN for three months >N0W
    since my birthday
    THEN from six o’clock NOW
    from now on
    three years ago_
    three years before THEN
    For details of the use of ago and before
  • We use for to say how long something lasts.
      [ for + period of time]
      I once studied the guitar for three years.
      That house has been empty for six weeks We go away for three weeks every summer.
      My boss will be in Italy for the next ten days.
      When we talk about a period of time up to the present, we use for with the present perfect tense (have + past participle).
      I’ve known her for a long time. (NOT Iknow-her . . .)
      A present progressive with for often refers to the future.
      How long are you staying for? ( = Until when . . .)
      We can leave out for with How long . . .?
      How long are you staying ?
      How long have you been waiting?
  • From and since give the starting point of an action or state: they say when something begins or began.
    from/since + starting point
    I’ll be here from three o’clock onwards.
    I work from nine to five.
    From now on, I’m going to go running every day. From his earliest childhood he loved music.
    I’ve been waiting since ten o’clock.
    I’ve known her since January.

    Since gives the starting point of actions and states that continue up to the present; from gives the starting point of other actions and states.
    THEFT from nine to five >TH£N
    THEtf from his childhood
    from three o’clock onwards NOW from now on

    THEtf

    since ten o’clock

    *~N0W

    since January
    For and since can both be used with the present perfect (have + past participle). They are not the same.

      [ for + period] [ since + starting point]
      I’ve known her for three days. I’ve known her since Tuesday.
      I ‘ve been here for a month. I ‘ve been here since July.
      I’ve had my car for ages. I’ve had my car since 1980.