The Hidden Evidence: The Past Family
The present-day explanation for English tense depends much on a falsehood, hiding away the Past Family -- past time adverbials such as "in the past, in the past year, within the past two months, during the past three decades, over the past four weeks, for the past few years".
All grammar books hide away these past time adverbials for Present Perfect and then
preach that past time adverbials are not compatible with Present Perfect:
Ex: *I have seen him yesterday.
But the fact is, as we all well know, the Past Family are quite compatible with Present Perfect:
Ex: I have seen him in the past few days.
How shall we teachers tackle with this problem of hiding? Your opinion is appreciated.