11/25/2014

FOR and SINCE - present perfect

The use of FOR

We use For when we measure the duration – when we say how long something lasts.
For + a period of time
To measure a period of time up to the present, we use the present perfect tense and not the present tense.
  • I have known her for a long time. (Correct)
    know her for a long time. (Incorrect)
  • have lived here for ten years. (Correct)
    live here for ten years. (Incorrect)
The present tense with For refers to a period of time that extends into the future.
  • How long are you here for? (Until when)
  • How long have you been here for? (Since when)


The use of SINCE

Since gives the starting point of actions, events or states. It refers to when things began.
Since + a point in time (in the past), until now.
  • I've been waiting since 7 o'clock.
  • I have known him since January.
With since we use the present perfect tense or the past perfect tense.
  • have been here since 5 o'clock and I am getting tired.
  • had been working since 5 o'clock and I was getting tired.
Since can also be used in the structure It has been + period of time + since.
  • It has been two months since I last saw her.
  • It has been three years since the last earthquake.



EXERCISES


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