Я пишу письмо. I am writing a letter. Вчера я написал письмо. Yesterday I wrote a letter.
ASPECTS: IMPERFECTIVE and PERFECTIVE
The Russian verb has three tenses and two aspects: imperfective and perfective. The aspects are used to define the mode of the action expressed by the verb.
- For actions that are actually taking place, that are repeated or continuous, or for permanent states, with no indication of the start or end of the action: use the imperfective aspect.
- For a single action, an action which is complete or which is considered to be limited or which has a clear result: use the perfective aspect.
Russian verbs therefore are in aspect pairs, with each of the aspects having its own nuance. Most verbs have two aspects: imperfective and perfective.
Imperfective
perfective
Perfective verbs are used only to form past and future tenses, whereas imperfective verbs are used to form present, future and past tenses.
учить (imperfective)
выучить (perfective)
HOW TO TELL THE ASPECT OF A VERB?
- If in an aspect pair (imperfective / perfective), only one of the two forms includes a prefix, this form is the perfective:
imperfective → perfective
читать → прочитать (toread)
мочь → смочь (to be able to)
imperfective → perfective
учить → выучить (to study/to learn)
писать → написать (to write)
Exception: покупать → купить (to buy) etc…
- If both infinitives of an aspect pair end in -АТЬ or in -ЯТЬ, the shorter of the two infinitives is the perfective:
imperfective → perfective
рассказывать → рассказать (to tell)
imperfective → perfective
понимать → понять (to understand)
- If the aspect pair has one infinitive ending in -ЕТЬ, -ИТЬ or -НУТЬ and the other in -АТЬ or in -ЯТЬ then the former is perfective and the latter is imperfective:
imperfective → perfective
отдыхать → отдохнуть (to rest)
повторять → повторить (to repeat)
imperfective → perfective
умирать → умереть (to die)
приглашать → пригласить (to invite)