Is the following sentence correct? - I've tried to send this email three times this morning. I don't know what's wrong.
Correct.
Is the following sentence correct? - I'm getting really angry, this is the third time I am telling you to do your homework!
[...] third time I HAVE TOLD you [...]
Is the following sentence correct? - I am living in this house since I was a child.
I HAVE LIVED in [...]