It should have been done a long time ago.

I haven't seen you for so long.

in a long ago

way back

Way back, in a long ago people didn't have any religions. / Давным-давно у людей не было никаких религий.

I should have done that a long time ago.

We've been friends a long time.

I've been wanting to try this.

Как давно это было? перевод на английский

How long ago was that?

это было давно перевод на английский

It was many years ago.

мы не виделись очень давно перевод на английский

We haven't seen each other for a long time.

давно хочу это сделать перевод на английский

I've wanted to do that for a long time.