Russian verb has two aspects: imperfective and perfective. Usually when you start to learn Russian you learn imperfective verbs only. Later you learn that almost every verb has its perfective aspect.
We use the imperfective aspect for verbs in two cases:
- when we are focusing on the process of action
- when we mean a general action (usually, sometimes, always, often, many times etс.)
- Вчера я писал письмо 2 часа – Yesterday I was writing a letter for two hours. (focus on the process)
- Я писал письма каждый день – I wrote letters every day. (many times)
We use the perfective aspect when we want to focus on the result:
Я написал письмо. Оно на столе. – I have written my letter. It is on my desk. (I focus on the result – the finished letter is on my desk)
Look at the other example to feel the difference between imperfective and perfective aspects:
Она готовила суп.
Она приготовила суп. Cемья сейчас ужинает.