[Grammar] until I took ... I've been/ I'd been

[Iryn_]

Hello, dear forum users!

Until I took this course, I've been learning/ 'd been learning English from textbooks only.

Is Past Perfect Continuous the only option here because 'took' is in Past Simple? Or may it depend on how long ago I 'took' it?
e.g. if I imply I took the course a month ago - had been trying,
if I imply I took the course, say, yesterday or today - have been trying

 

[GoesStation]

Only the past perfect continuous works. (Note that we don't capitalize the names of tenses.) It would be more typical not to contract I'd in your sentence, though it's not impossible.

It would be more natural to say Until I took this course, I was only learning/studying English from textbooks.