In my English book it says ''I have done'' is used when an action is ended, but where there are consequences in the future. For example: 'There has been an accident, and as a result the street is blocked'.
I understand how to use it, but I am puzzled about the difference with the present perfect continuous' For example: 'It has been raining (and now the street is wet)'. Why could we not use the present perfect?
Why can't we say ''It has rained''? When should we use the present perfect and when the present perfect continuous?