Learn English – Can we say “it’s said to have been…”

Looking at the last few lines, I see that you are a bit confused about 'went' and 'been'. Well, as far as 'visiting' or 'going' to places is concerned, 'went' talks mainly about a one time event whereas 'been' talks about going and coming back.

I've just been to the bank -I went and came back from the bank.

On the other hand, if you say...

I just went to the bank- talks about your presence in the bank (probably a one time event). For instance, you tell your mom at home that if your friend comes asking you, she may reply that you 'just went' to the bank.

In the same scene, when your friend is waiting for you and you arrive at your home, you can tell him that you have just been to the bank. So, 'Just been here is -went, finished the work, came back'.

Remember the nursery rhyme? Pussy cat pussy cat where have you been? So, here, the cat had gone and came back! :)

I agree with those in the comments, that using "What [were you]/[have you been] doing?" is much more likely to be interpreted by the recipient as rude, or at least intrusive. I can't think of a situation in which I would use either of these phrases unless I was essentially accusing someone of doing something they shouldn't have been.

If I'm interested in what someone has been doing, instead of saying "What were you doing last week?", I might say "What did you get up to last week?", although if the last time I spoke to them was much more than a week ago and there's no specific reason why last week was important, then I'd probably just say "What have you been up to?".

Disclaimer: I'm a native UK English speaker, so some of the above might be a little regional to the UK. I have spent a fair bit of time in the US and understand a decent amount of their regional variations, but I'll let a native US English speaker fill in the gaps if necessary.