Quote Originally Posted by ShakeyX View Post
Then I might say "So is that the correct aspect, I couldn't use покупал could I?" And several natives Russians answer, "Yes you can use the imperfective". But here lies the problem. As English doesn't have Imperf/Perf there is no real way to translate them, although attempts have been made by some books using "bought/was buying". So both aspects equal the same thing in English, but the backstory is I guess what dictates which you should use, and by doing one sentence examples and asking if both could be used, i guess russians would say yes, both WORK, but do they convey what I am actually trying to express.
Well, at least English has the distinction of simple vs. progressive, which isn't entirely the same thing but similar enough... "Yesterday I bought fish" conveys the idea of a complete activity resulting in the possession of fish. That's купить, perfective. "Yesterday I was buying fish" describes how you spent your time. You may have ended up in the possession of fish or even failed to obtain any fish, the result is not important. That's покупать, imperfective.

The main distinction between English and Russian in this case, as far as I see it, is that there is no present tense perfective in Russian, whereas there is a simple present tense in English. I get the impression that if you choose the perfective verb when you would express the idea in English using a simple tense and you are talking about a specific event in past or future, then you will be right more often than wrong.