I guess I'll explain myself to get the ball rolling.
What we teach as 'tenses' are not really tenses but combinations of aspects and tenses. So, present perfect progressive(continuous) is in fact
Present tense + perfect aspect + progressive aspect
Perfect adds the meaning 'before' so since we are talking about the present perfect here it means before now. If we were talking about the past perfect it would mean before the point in the past I am referring to. Similarly for the future perfect.
The progressive aspect adds the idea of 'limited in duration'. So to look at a couple of example sentences:
I am driving.
In the first there is no limitation on the duration of the verb so it can only be interpreted as being a factual statement. It could answer the question 'How do you get to work?' and would not be referring to any particular time.
The second restricts the time to 'at this moment' and might answer the question 'What are you doing now?'.
Used with short duration verbs the progressive aspect makes the action repeat in order to fill the time period in question. Which is why sentences such as
'I have been cutting my finger.'
although grammatically correct - there is no difference in grammar between the above and "I have been cutting my toenails.' - feel uncomfortable to native speakers. To make sense of the former we have to come to the conclusion that the speaker is some kind of masochist since either they must have been cutting their finger either very slowly or repeatedly.
'Future tenses' are made from combinations of aspects, present verb forms and future markers such as 'will', 'could', 'might', etc.
Future time is often expressed by the use of unmarked present forms: 'going to', 'am doing' etc.
I feel that it is useful to explain the above to students. In my experience it is simpler to explain than the EFL tense system and helps to lead them to a clearer understanding of our language. I tend to do this at intermediate level. I am interested in the opinions of other teachers on this matter.
- For Teachers