Hi Rafrah,

Yes, the distinction between these tenses is often difficult to explain. For me, the Present Perfect Simple focuses on the action which has been completed, whereas the Present Perfect Continous focuses on the way in which the action has affected the speaker. "Why is you hair wet?" "I've been swimming." "Why have you put on weight?" "I've been eating too much."

If you make statements like "I've been teaching EFL for forty years." the focus is on your continuous experience and therefore your authority in commenting on methodology.

Remember that grammar is not an accurate reflection of the real world. A speaker's choice of grammatical pattern is a refection of the way the speaker feels about the event being described.

Another important point is that the Present Perfect Simple is used much more frequently than the Present Perfect Continuous, therefore the PPS should be given much greater teaching priority than the PPC.

So, the message to your students is "if you're not sure, use the Present Perfect Simple and you'll probably be correct."