Обойдешься без перевода, может быть, но на всякий пожарный (ведь под словом "особенно" подразумевается, что есть и неясности, кроме фразы "ограниченный пределом"), предлагаю вариант:

Usage of perfective (совершенный вид) verbs, which denote an action as a tangible and whole fact, possessing a limit; and imperfective (несовершенный вид) verbs, which denote an action as a process without a limit.
To echo others: at risk of gross oversimplification, the imperfective tends to be more "in your head," being more intentional, more "what you're thinking about," and thus harder to see than an action described by a perfective verb. When a Russian asks, "Кто выключал свет?" (as opposed to "Кто выключил свет?") there is no *physical* evidence that the light was turned off. Rather, the now-intangible actions of whoever turned off the light are being queried.