Knowing Lea began six years ago and is still true now. The present perfect links those two times. The negative example also spans time up to now: no conversation has occurred since Tuesday.

The idea

Use for with a duration: for six years. Use since with a starting point: since 2015, since they met. Ask How long have/has + subject + past participle...? State verbs such as know normally use the simple perfect, not the continuous.

Examples

  • I have known Lea for six years.
  • This shop has been here since 2015.
  • How long have you had this laptop?
  • We haven't spoken since Tuesday.
  • She has lived here for ten months.
  • They have been friends since they met at college.

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Watch out

For a continuing state, say I have known her for six years, not I know her since six years. For does not require a perfect tense: I lived there for a year can describe a completed past stay. The intended time span determines the tense.

Try it yourself

  1. Choose the correct option. I have known Lea ___ six years. (for / since)

    Show answer or example answer

    for

    Six years is a length of time, so choose for.

  2. Choose the correct option. This shop has been here ___ 2015. (for / since)

    Show answer or example answer

    since

    2015 names the starting point, so choose since.

  3. Choose the correct option. I have ___ Lea for six years. (know / known)

    Show answer or example answer

    known

    After have, use the past participle known. The state began earlier and continues now.

Use it today

Choose a friendship, possession and place of residence. Write how long each has continued, using both for and since. Add one How long...? question.