The difference between Imperfective aspect and Perfective aspect

When used as nouns, imperfective aspect means a feature of the verb which denotes an action or condition that does not have a fixed temporal boundary, but is habitual, unfinished, continuous, repetitive or in progress, whereas perfective aspect means the perfective aspect is a feature of the verb which denotes viewing the event the verb describes as a completed whole, rather than from within the event as it unfolds. for example, "she sat down" as opposed to "she was sitting down". since the focus is on the completion of what is expressed by the verb, this aspect is generally associated with the past and future tenses. this term is often used interchangeably with aorist aspect. this is not to be confused with the perfect tense.

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