Sometimes, I got really confused by the use of the Present Perfect tense. Given the fact, that we don't have this structure in Russian, all we can is to base our knowledge on grammar rules. 

The rules are quite simple: 

1. Experience: I have been to London twice.
2. Unfinished actions: I have lived in Moscow since I was born.
3. Close connection to the present situation: I have just cooked dinner.

However, when it comes to simple questions, all that grammar rules are not so obvious. For example, if I am not sure and want to re-ask, could I say something like 

> 
> Have you meant? or Did you mean?
> 
> 
> 

Another case: 

> 
> I've sent you the letter and I sent you the letter.
> 
> 
> 

Does the first mean that I have just done it and the second that it was some time ago? How do you use it?