Every now and then I come up with a sentence, that eventually undermines my confidence as to whether it's correct or not - just a part of my OCD issues I guess.
Same thing happened yesterday and since then I've been dwelling on that, unable to find any examples that could prop up my thesis. The sentence I formulated was:
Do you expect me to believe that you were running for 20 minutes flat?
My concern is: did I get tenses right or perhaps I should've used "had been running"? Can I use "for" and "since" with past continuous while I'm talking past unrelated to present, or are those used solely with perfect tenses? As in:
They were fighting Nazis for three days.
I was studying for six hours yesterday.
I was working there since I graduated from school.
These things are pretty basic, but I tell you: OCD may really get on your nerves and make you doubt your own skills. Therefore I just want to make sure if these are correct.