please look at my question carefully. It's not the difference btw Present Perfect and Past Simple or Present Perfect and Present Perfect Continuous. This topic isn't usually covered, but looking at the expanation,we could see such an explanation
Present Perfect - unfinished (I've lived there for four years - still live there) Past Simple - finished (I lived there for four years - most likely I don't live there anymore)
Present Perfect - I've done - likely I've finished the activity Present Perfect Continuous - I've been doing - besides other use, we mean that the activity is still in process - unfinished
I see a contradition in the explanation of the use of Present Perfect and Past Simple - both can be used for finished action. What's the difference then? Only if I use particular tense markers?
I got puzzled after seeing this expanation in the The book Roadmap B1
Use the present perfect simple to focus on the completed action. It often explains how much or how many (including none). The birth rate has fallen since the 1960. (how much) COULD we say the same using the Past Simple if omit since the 19603 - will it mean the same&
Use the present perfect Continuous to focus on an action that lasts for a period of time and/or that is unﬁnished now. It often explains how long.
Scientists have also been exploring other ways to use the sun‘s energy. (action unﬁnished)
hope, that's clear