I say that because that's the way I see it after 75+ years as a native speaker, 55+ years as a teacher, 50 years as an amateur grammarian and 24 years as a responder in English language forums.
It sounds like you're a little frustrated and stressed out. Cheer up! There's nothing to be so sad about!
Just to explain to you (not just to you, 5jj, but anyone who might read this) exactly what it is that confuses English students about this logic:
Here (link to the YouTube video), the guy says
"I ran every day for 30 days" instead of
"I was running every day for 30 days". OK, fine, he's a native speaker, this is how they talk. But... you said that the continuous aspect works "
very well, suggesting to duration of this activity", didn't you?
I had been running three miles a day for three years before/when I broke both legs.
When is good. Before suggests to me that breaking both legs was foreseen.
I had run three miles a day for three years before/when I broke my legs.
Neither works particularly well. the continuous aspect works very well, suggesting to duration of this activity,
So why didn't that guy use the aspect that you say "
works very well" (but instead used the aspect that you say doesn't work "
particularly well")
?
- I'd been running every day for 30 days when I broke my leg.
- I'd run every day for 30 days when I broke my leg.
Why out of these two (above), the one with the continuous aspect "
works very well, suggesting to duration of this activity" (unlike the one with the simple aspect that doesn't work "
particularly well")
while in the other two (below) the one with the simple aspect works just fine on its own?
- I ran every day for 30 days.
(
original screenshot)
- I was running every day for 30 days.
(edited screenshot)
How does adding "when I broke my leg" create this need for the continuous aspect?
And why is it that without the "when I broke my leg" this need for the continuous aspect suddenly disappears and the simple aspect all of a sudden starts working well on its own?
1. to explain things to you so that you understand them;
2. to get you to realise than it is not possible to explain every single English utterance in terms of what English grammar books, even very advanced ones say. We have far more grey areas and flexibility than you seem prepared to accept.
Don't confuse yourself. It's not just me. This is one of the most frequent questions I hear from my students. Lots of other people wish to solve this problem too, except that they are often shy of being pushy, and therefore quickly give up before finding the answer.