In the lesson it says: In French, you use pour + [durée] only to express a duration in the future., however in Lawless French:
https://www.lawlessfrench.com/grammar/depuis-vs-il-y-a/?fbclid=IwAR2Yy7q_glAFPUv54NKv_xYP9EW4oqW84FTg9NIggZZ3CBgjSxE3JPbHAbc
Pour and pendant can replace depuis only when the verb is in the past tense.
J’étudiais pour / pendant quatre heures quand il a téléphoné. I’d been studying for four hours when he called.J’étais anxieux pour / pendant deux semaines. I’d been anxious for two weeks.It seems to contradict this. So I am confused. Can someone clarify please.