I explained to my student that the Present Perfect Continuous is used for emphasis on the repetitive nature of an activity. Can someone explain why the Present Perfect Simple is used in the phrase:
It's the third time I have shown you how to do it.
when "third time" is a repetitive action?
It's the third time I have shown you how to do it.
The main reason it is used in your sentence is this:
The actual moment in the past when this action of showing occurs is not specified or relevant to the speaker, just the fact that it is IN the past.
Compare it to: Yesterday was the third time I showed you how to do it.
In this case, it has nothing to do with repetition. It has to do with the past moment not being specified or specific. It's just past [finished]. You want to say the thing occurred in the past without specifically saying when in the past it occurred.
This non-specified use of present perfect is different from:
I have never eaten fish. [That means, until now, and up to this moment, I have not eaten fish.]
the present perfect simple is used after: this is the third time that…, it is the first time that…, etc.
Because it is the first time you've been showing how to do it.
Until the second time you've shown it, it was not recognised as an repetitive action. Then, the third time you've done it, it became a repetitive action.
In this case, the action done three time is "to show how to do", not "to continuously show how to do".
If you put "It's the third time I've been...", it means like:
Day 1: I've shown it many times.
Day 2: Again, I've shown it many times.
Day 3: AGAIN, I've shown it many times. Oh, This is the third time I've been showing you how to do it!
