Hi ! i think you got answer. I am Kaushal . I wanna learn Japanese language. Can you help me? My e mail : [email protected] and [email protected] . Please help me .. i am waiting. i hope you reply soon. i can not send you messages. so i write here.

Yes, "for a long time" has the nuance of occurring for a long period of time e.g. months, years etc. As for "for a while" means more over a period of maybe a few hours. The nuances in your examples are in the following: I didn't study for a while = I didn't study for a few hours I didn't study for a long time = I didn't study for months or years I hadn't studied for a while = I hadn't studied for a few hours I hadn't studied for a long time = I hadn't studied for months or years.