Всем привет!

I’ve got some good news and some bad news.

The bad news is that this gigantic article is 100% Russian grammar and I know how much you love grammar!

The good news is that we will attack one of the most important subjects of the Russian grammar that most learners find difficult: The Verb Aspects, or simply, Imperfective and Perfective verbs.

You will learn all the different scenarios in which we use an imperfective or a perfective verb. I have also drawn sketches which will help you to visualise and understand better each scenario.

I’ll introduce you to two very useful online tools so you can instantly get access to perfective/imperfective pairs and verb conjugation tables.

Finally, this time you’ll have more fun testing yourself because I’ve prepared an interactive multiple-choice quiz for you!

After reading this article, I guarantee that you will know when to “go imperfective” and when “to go perfective”!

Perfective & Imperfective Verbs in a nutshell

Perfective Verbs describe actions that have been completed or will be completed. They can’t express actions in the Present Tense, i.e. actions that are happening now.

Perfective verbs describe actions with respect to a particular time; the events are not general.

Perfective verbs have a “DONE” taste: I’ve done it! I’ll get it done! I’ll have it done by 18:00 tomorrow.

Perfective verbs focus on results: I’ve finished my dissertation. I’ve read a whole book. I’ve cleaned the house. I booked the flights. I bought the tickets. I’ll do the shopping tomorrow. I’ll have recorded 10 songs by end of next week.

Perfective verbs describe actions of limited duration: I’ll take a short nap. I’ll do a little bit of studying. I’ll sit down for a bit. 

The results of perfective verbs are still in effect. If you “did and undid something”, you can’t use a perfective verb!

 

Imperfective Verbs are used to describe uncompleted actions.

Imperfective verbs describe something that you are doing now, or something that you used to do/do/will be doing regularly (repeated/habitual actions).

Imperfective verbs focus more on the action itself rather than a particular outcome: I read books. I go to the cinema every now and then. I’ll be cycling a lot in the summer. I used to go swimming.

Imperfective verbs focus more on the duration of the action. They have a “STRETCH” taste!  I was studying the whole evening yesterday. I’ve been working a lot. I’ll be listening to music for the next few hours. 

 

Perfective-Imperfective-Summary

Perfective Verb Uses

Let’s explore all the different uses of the perfective and imperfective verbs. Just three points on the diagrams and abbreviations before we start:

  1. The letter P on the time diagrams below denotes the Present (now).
  2. Pf means perfective and impf means imperfective.
  3. The diagrams precede the relevant examples.

Completion of an action with attendant result

When the focus is the completion and the result of an action, we use a perfective verb.

 

Completion of an action with attendant result - Past

Она прочитала письмо, и теперь она всё понимает. – She has read the letter and now she understands everything (the result is explicit here: “now she understands everything”).

прочитать – to read (pf)

 

Он вымыл посуду. – He washed the dishes (as a result, the dishes are now clean).

вымыть – to wash (pf)

 

Он поужинал. – He dined (as a result, he isn’t hungry any more).

поужинать – to dine (pf)

 

Она решила десять задач. – She solved ten problems (a number here – ten – makes the attendant result clear).

решить – to solve (pf)

 

Она позвонила ему, как только узнала новость. – She called him as soon as she heard the news.

The word как только implies here the completion of an action – as soon as she heard the news. Also, she has called him – the call is completed.

узнать – to know, find out, hear, learn (pf, this verb has lots of meanings, please see here)

позвонить – to call (pf)

 

Наконец мы пришли домой. – Finally, we got home (the word наконец implies here the completion of an action).

прийти – to arrive on foot (pf)

Screen Shot 2016-06-13 at 14.03.22

Завтра я обязательно напишу тебе письмо. – Tomorrow I will definitely write a letter to you (the word обязательно here makes it clear that the job will be completed tomorrow).

написать – to write (pf)

 

Она сдаст экзамен и поступит в университет. – She will pass the exam and enter University.

сдать – to pass an exam (pf)

поступить – to enter (school, university), to behave, to act

Be careful with the stress of this verb – поступлю, поступишь, поступит, поступим, поступите, поступят

 

Sequential Actions

When a single action follows another in sequence, the two actions are expressed with a perfective verb.

Screen Shot 2016-06-13 at 14.26.14

Он встал, посмотрел на него и засмеялся. – He stood up, looked at him and started to laugh.

встать – to stand up (pf)

посмотреть – to look (pf)

засмеяться – to start to laugh (pf)

 

Когда дождь кончился, мы вышли на улицу. – When the rain stopped, we went out to the street.

кончиться – to stop, finish (pf)

выйти – to go out (pf)

Screen Shot 2016-06-13 at 14.30.45

Я приеду и скажу тебе правду. – I will come and tell you the truth.

приехать – to arrive by means of transport (pf)

сказать – to say, to tell (pf)

 

Я открою бутылку и выпью вина. – I will open the bottle and drink some wine.

открыть – to open (pf)

выпить – to drink (pf)

Wanna speak Russian well?

Instantaneous Actions

Perfective verbs are used to express an action that takes a very limited amount of time, i.e. an instantaneous action.

Screen Shot 2016-06-13 at 14.51.56

Он прыгнул в воду. – He jumped into the water.

прыгнуть – to jump (pf)

 

Она крикнула. – She gave a shout.

крикнуть – to give a shout (pf)

It’s conjugated just like прыгнуть above.

(крикну, крикнешь, крикнет, крикнем, крикнете, крикнут)

 

Учитель ударил по столу. – The teacher gave a rap on his desk.

ударить – to hit (pf)

 

The very beginning of an action

Certain perfective verbs denote only the starting point of an action and are typically formed with various prefixes.

Screen Shot 2016-06-13 at 15.11.06

Вдруг ребёнок закричал. – The baby suddenly started to cry.

закричать – to start to cry (pf)

 

Сын увидел отца и побежал к нему. – The son saw his father and started running towards him.

увидеть – to see (pf)

побежать – to run (pf)

 

Она прочитала письмо и заплакала. – She read the letter and started weeping.

заплакать – to start crying (pf)

 

Actions of Limited Duration

Screen Shot 2016-06-13 at 15.25.36

Мы посидели и поговорили. – We sat for a while and had a talk.

посидеть – to sit down for a bit (pf)

поговорить – to talk (pf)

 

Хочешь поспать чуть-чуть? – Do you want to have a nap for a while? (The word чуть-чуть shows the small duration of the action.)

поспать – to have a short nap (pf)

 

Мы поиграли немного в шахматы. – We played chess for a while. (The word немного shows the small duration of the action.)

поиграть – to play (pf)

 

Она почитала и потом поехала на работу. – She read for a while and then went to work (Don’t confuse with прочитать which denotes completion of an action as we saw earlier.)

почитать – to read for a short while (pf)

Screen Shot 2016-06-13 at 16.27.17

Мы посидим и подумаем. –  We will sit for a while and think.

посидеть – sit for a while (pf)

подумать – think for a while (pf)

 

Я посплю до урока. – I will have a nap before the lesson.

поспать – to have a short nap (pf)

 

Actions completed in specific amount of time

A perfective verb is used with the preposition за + Accusative case of time to express how long it took to complete an action. To ask a question of the type “How long did it take to…” , one asks “За какое время…?”. 

Screen Shot 2016-06-13 at 16.36.30

За какое время ты решил задачу? – How long it took you to solve the problem?

решить – to solve (pf)

 

Он выучил русский язык за год. – It took him one year to learn Russian.

выучить – to learn (pf)

Imperfective Verb Uses

Action in progress (any tense)

Screen Shot 2016-06-13 at 19.22.35

If we are talking about an action that is happening now, we can only use an Imperfective verb. This is the equivalent of the Present Continuous in English (I’m doing something now).

Я слушаю музыку (сейчас). – I am listening to music (at the moment).

слушать – to listen (impf)

 

Он не может говорить по телефону, потому что работает. – He can’t speak on the phone because he’s working.

работать – to work (impf)

 

Screen Shot 2016-06-13 at 19.31.10

We use an Imperfective verb to describe an action that was happening in the past. This is the equivalent of the Past Continuous in English (I was doing something).

Он целый день смотрел телевизор вчера. – He was watching television all day yesterday (целый emphasises on the duration of the action).

смотреть – to see, to watch (impf)

 

Мы говорили с ним весь вечер. – We (I and he) were talking for the whole evening (весь emphasises on the duration of the action).

говорить – to speak, to talk (impf)

 

Москва не сразу строилась. – Moscow wasn’t built in an instant (it was being built for long time – Phrase from the famous song Александра featured in the Soviet film Москва слезам не верит).

строиться – to be built (impf, reflexive)

 

Screen Shot 2016-06-13 at 19.48.32

We use an Imperfective verb to describe an action that will be happening in the future. This is the equivalent of the Future Continuous in English (I will be doing something).

Петя завтра будет работать до вечера. – Petya will be working tomorrow until the evening.

Я буду работать над этим всю ночь. – I’ll be working all night on this.

работать – to work (impf)

Wanna speak Russian well?

Repeated or habitual actions (any tense)

Screen Shot 2016-06-13 at 20.04.53

Каждое утро он пьёт кофе с молоком. – Every morning he drinks coffee with milk.

пить – to drink (impf)

 

Я хожу в парк раз в неделю. – I go to the park once a week.

ходить – to walk, to go (impf)

Screen Shot 2016-06-13 at 20.15.25

Когда мы учились в университете в Москве, часто встречались. – We used to meet often when we were studying in the university in Moscow.

учиться – to study (impf)

встречаться – to meet (impf)

 

Я несколько раз перечитывал Анну Каренину. – I’ve read Anna Karenina several times.

перечитывать – to read again and again (impf)

Note here that читать – to read is imperfective,  the prefix пере- makes the verb перечитать – to reread perfective, and we change to перечитывать to make the verb reread imperfective again and give it a habitual meaning.

 

Иногда она купалась в озере. – Sometimes she swam in the lake.

купаться – to swim (impf)

Screen Shot 2016-06-13 at 20.43.37

С этих пор я буду заниматься спортом. – From now on I will be doing sports.

заниматься – to do, to study, to practice (impf)

 

В Москве я часто буду ходить в кино. – In Moscow I’ll be often going to the cinema.

ходить – to walk, to go (impf)

Mixed Scenarios

Below, we are going to explore some scenarios in which both perfective and imperfective verbs can be used but the meaning changes in each case.

Reversed (cancelled) actions

An imperfective verb is used to show that an action was done and then undone – for instance that a window was opened and then closed again.

Screen Shot 2016-06-16 at 13.41.52

Кто открывал окно? – Who opened the window (and then closed it again)?

открывать – to open (impf)

 

Note the difference in the above example if we use the perfective verb открыть – to open:

Кто открыл окно? – Who opened the window (and left it open)?

 

Let’s look at another example to get the point here.

Зачем ты вечером вставал с постели? Ты болен и должен лежать. – Why were you out of bed last night? You are sick and should stay in bed. (he got out of bed and went back).

вставать – to stand up, to get out of bed (impf)

 

Зачем ты встал с постели? Ложись же сейчас в постель. – Why have you gotten out of bed? Go back to be right now! (at the moment of speaking he is out of bed)

встать – to stand up, to get out of bed (pf)

The verbs that can express a cancelled action typically involve move or change in position, i.e. get up/lie down, open/close, turn on/turn off, etc.

Imperfective-Perfective-Verbs

Denial of an action – “I didn’t do this!”

When you want to deny having done something, you have to use an imperfective verb.

Remember that perfective verbs imply an intention to do something. If you deny having done something, you had no intention of doing it – so go for an imperfective verb!

For example:

Саша, ты взял мою книгу? – Sasha, did you get my book?

взять – to take (pf)

Я не брал твою книгу! – I didn’t take your book!

брать – to take (impf)

You see that although the structure of the question and the answer is the same, Sasha doesn’t use the perfective form взять as that would mean that he did have indeed an intention to get her book but he didn’t manage to get it in the end!

If he did have an intention, he would use perfective: Я хотел взять, но не взял! – I wanted to take it but I didn’t!

 

cat-didnt-do-it-expolorerussian

съесть – to eat (perfective)

есть – to eat (imperfective)

Expected – Unexpected Actions

Screen Shot 2016-06-16 at 15.31.04

A perfective verb implies result, intention, or expectation! On the contrary, a negated imperfective verb can mean that the action wasn’t expected to take place. For example,

Вы получили моё письмо? – Did you receive my letter?

получить – to receive, to get (pf)

Нет, мы еще не получили. – No, we haven’t received it yet (but we’re expecting it).

But…

Нет, мы никакого письма не получали! – No, we haven’t received any letter! (What letter are you talking about???)

получать – to receive, to get (impf)

 

In the same way, when the speaker is interested in finding out if an action has taken place, an imperfective verb should be used. The focus is not the result. They are just asking whether something has happened. For example,

Вы читали книгу “Анна Каренина”? – Have you read the book Anna Karenina?

Да, читал. –  Yes, I’ve read it.

читать – to read (impf)

But…

If the speaker is interested in the completion of the action, a perfective verb should be used. For example,

Вы прочитали отчёт? – Have you read the report (Have you finished reading the report)?

прочитать – to read (pf)

Achievement of Intended Result

Sometimes the imperfective verb is used to express that you’re trying to achieve something whereas its perfective pair signals that you have succeeded or failed. Have a look at the following examples:

Я всё утро вспоминал её имя и наконец вспомнил. – I was trying to recall her name all morning and finally I remembered it!

вспоминать – to remember (impf – lengthy, continuous process)

вспомнить – to remember (pf)

 

Он поступал в университет, но не поступил. – He applied to the university, but he didn’t get in.

поступать – to apply to university (impf)

поступить – to get into university (pf)

Wanna speak Russian well?

Infinitive

Let’s look at infinitive forms now. When shall we use a perfective infinitive and when an imperfective one?

The rules are not any different than the ones we explored above.

Continuous or Repeated Process – Imperfective Infinitive

If we’re talking about a continuous process that takes time, we should use an imperfective infinitive. For example,

Вечером я должен писать письма друзьям. – In the evening I have to write letters to friends.

 

If you’re talking about a repeated process, again go for an imperfective infinitive. For example,

Мой друг просил меня писать ему чаще. – My friend asked me to write him more often.

Verbs expressing Beginning, Continuation, End of a Process – Imperfective Infinitive

Он начинал читать “Война и мир”. – He started to read “War and peace”.

Он продолжил работать до вечера. – He continued to work until the evening.

Он перестал работать. – He stopped working.

Наконец, он бросил курить. – Finally, he quit smoking.

You see that all the above verbs that express beginning, continuation, or end already provide a limitation of the action with respect to time (he started, he carried on, he stopped, he quit). The use of a perfective verb would sound awkward here. On the contrary, an imperfective verb sounds more natural.

Verbs of learning or becoming accustomed – Imperfective Infinitive

With verbs of learning and becoming accustomed we use an imperfective infinitive because the focus is on the action. For example,

Он привык исполнять свои обещания. –  He’s accustomed to keep his promises.

Он привык жить в Лондоне. – He is used to living in London.

Она учится водить машину. – She is learning to drive a car.

Focus on Result – Perfective Infinitive

If now you want to focus on a result that needs to be achieved, go for a perfective infinitive. For example,

Я должен написать письмо другу завтра утром. – I need to write a letter to my friend tomorrow morning.

Modal Expressions

With modal expressions (Мне нужно, мне надо, можно etc.) if the action you’re talking about is specific/one-off occasion choose a perfective verb. If it’s something that happens regularly (things like “I need to be going, I have to be getting…” etc.) use an imperfective infinitive. For example, note the difference:

Мне нужно принять аспирин. – I need to take an aspirin (one instance – for example, I am not feeling very well today).

принять – to take (pf)

But…

Мне нужно принимать аспирин. – I need to take aspirin (regularly- for example, the doctor said it’s good for my blood pressure).

принимать – to take (impf)

Imperative

In English, you may use only one imperative form: Do this. Open the window. Read the book. 

In Russian, perfective and imperfective verbs have their corresponding imperative forms that are used for different scenarios.

Affirmative Imperative

Single occasion – Perfective Verb

Запишите мой телефон. – Write down my number.

записать – to write down (pf)

 

Закройте, пожалуйста, окно. – Close the window please.

закрыть – to close (pf)

 

Позвоните мне в 7 часов. – Call me please at 7 o’clock.

позвонить – to call (pf)

Repeated Action/General Advice – Imperfective Verb

Пиши мне часто. – Write to me often.

писать – (impf)

 

Ты спеши, ты спеши ко мне, если я вдали, если трудно мне. – You run, run to me, (every time) when I’m away, when I’m in trouble. This is from a famous song Не спеши.

спешить –  to hurry up  (impf)

 

Покупайте овощи в этом магазине. – Buy vegetables in this shop.

покупать – to buy (impf)

 

Impatience – Imperfective Verb

You remember above that when we want to ask someone to open the window we say:

Закройте, пожалуйста, окно. – Close the window please.

закрыть – to close (pf)

If they don’t open the window and you want to express your irritation/impatience, you use the imperfective imperative:

Закрывайте уже окно! – Get a move on and close the window for God’s sake! 🙂

закрывать – to close (impf)

 

Let’s have a look at another two examples:

Расскажи, что случилось. Что же ты молчишь? Рассказывай! – Tell me what happened. Why are you keeping silent? Go ahead, tell me then!

рассказать – to tell – pf (я расскажу)

рассказывать – to tell – impf (я рассказываю)

 

Возьми эти деньги. Они тебе будут нужны. Ну, чего ты ждёшь? Бери! – Take this money. You will need it. What are you waiting for? Take it!

взять – to take – pf (я возьму)

брать – to take – impf (я беру)

 

Polite Requests/Invitations – Imperfective Verb

Polite requests and invitations require an Imperfective imperative. For example,

Входите. – Come in.

входить – to come in (impf)

 

Приходите. – Come over.

приходить – to come over (impf)

 

Раздевайтесь, пожалуйста. – Take off your suit/coat please.

раздеваться – to undress (impf)

 

Садитесь, пожалуйста. – Have a seat please.

садиться – to sit down (impf)

 

Берите. – Take one/some.

брать – to take (impf)

Negative Imperative

In negative imperative we use imperfective forms even if the action is just one single instance. Note the difference in the affirmative/negative pairs below:

Откройте, пожалуйста, окно. – Open the window please.

открыть – to open (pf)

Не открывайте, пожалуйста, окно. – Don’t open the window please.

открывать – to open (impf)

 

Посмотрите этот фильм. – Watch this film.

посмотреть – to watch (pf)

Не смотрите этот фильм. – Don’t watch this film.

смотреть – to watch (impf)

 

Спросите его об этом. – Ask him about this.

спросить – to ask (pf)

Не спрашивайте его об этом. – Don’t ask him about this.

спрашивать – to ask (impf)

 

A perfective verb is used in a negative imperative when you want express a meaning like this: “Don’t do this … in order to avoid the bad consequences.” For example,

Не упадите, здесь скользко. – Don’t fall, it’s slippery here.

упасть – to fall (pf)

 

Не забудьте! – Don’t forget!

забыть – to forget (pf)

 

Смотри, не опоздай опять! – Don’t be late again (you’d better not be late again!).

опаздать – to be late (pf)

Wanna speak Russian well?

Tools for finding Perfective/Imperfective Pairs

In this section I’d like to introduce you to a couple of powerful web tools to determine the aspect of verb, find its aspectual pair, and also find out how it’s conjugated.

Wiktionary

Wiktionary is ideal for determining whether a verb is perfective or imperfective.

Let’s take for example the verb говорить – to speak. Open up Wiktionary and search for говорить in the search bar.

Wiktionary---to-speak

In the result page you will see on the top basic information about the verb. Next to the verb you’ll either see the tag impf or pf meaning that the verb is imperfective or perfective respectively. The verb говорить is imperfective; it’s marked with impf as you can see in the screenshot below:

 

wiktionary-results

 

Next to the each verb, you will see its perfective/imperfective pair. For говорить we have two associated perfective pairs for each of its two meanings (сказать – to say/tell, поговорить – to speak). The verbs are clickable, so click on them to open up their respective pages.

If you scroll further down you can also see how the verb is conjugated.

conjugation-wiktionary

You see above that since the verb is imperfective it has Present Tense – Я говорю. If the verb is Perfective, you will notice that the Present Tense column will be empty and it will have only Future and Past Tense.

For example, have a look at the table of сказать in Wiktionary.

To-say---perfective-wiktionary

You’ll find most of the Russian verbs in Wiktionary. Just make sure when searching that you look always look at the Russian section as certain forms are identical across other Slavic languages.

Starling Conjugator

In Starling conjugator you’ll find conjugation for almost all the Russian verbs. In case you can’t find a verb in Wiktionary, look it up on Starling and vice versa. This is the result you get after searching for говорить.  Notice the verb is marked нсв which means несовершенный – imperfective. For perfective verbs you will see the tag св – совершенный – perfective.

Starling-conjugator

 

Quiz Answers – Notes

  1. Мы целый год привыкали к жизни в этом маленьком городке, но так и не привыкли. – For a year we have been trying to get used to living in this small city, but we didn’t manage in the end.
    привыкать – to get used (impf), привыкнуть – to get used (pf), Achievement of Intended Result
  2. Мы посидели немного, отдохнули и пошли дальше. – We sat for a while, got some rest and went further.
    посидеть – to sit for a while (pf), Action of Limited Duration
  3. Утром после завтрака они долго гуляли по городу. – In the morning after breakfast, they were walking around the city for a long time.
    гулять – to walk (impf), Action in progress/Long Duration
  4. Я долго думал об этом. Наконец, я принял решение. – I was thinking about this for long. Finally, I reached a decision.
    думать – to think (impf), Action in progress/Long Duration
  5. Всё утро шёл дождь. – It was raining all morning.
    идти (impf) – дождь идёт – It’s raining, Action in progress/Long Duration
  6. Он вчера встал поздно, в десять часов. Летом он всегда вставал рано, в семь часов. – He got out of bed late yesterday, at 10 o’clock. In the summer, he always used to get out of bed early, at 7 o’clock.
    встать – to stand up, get out of bed (pf), вставать – to stand up, get out of bed (impf) The first sentence refers to an one-off instance (single action – yesterday) whereas the second refers to a habitual action in the past (in the summer).
  7. Девочка плакала весь день. – The girl was crying all day.
    плакать – to cry (impf), Action in progress/Long Duration
  8. Когда девочка узнала о смерти бабушки, она заплакала. – When the girl was told about the death of the grandmother, she started crying.
    заплакать – to start crying (pf), Verb expressing the very beginning of an action
  9. – Почему ты не носишь свою новую рубашку? – Why are you not wearing your new shirt?
    – Я её вчера надевал. – I was wearing it yesterday.
    надевать – to wear (impf) Reversed/cancelled action (He is not wearing the shirt any more)
  10. Она вчера не сдала экзамен. Она плохо подготовилась. – She didn’t pass the exam yesterday. She didn’t prepare enough.
    сдать экзамен – to pass an exam (pf), Verb which denotes the successful completion of an action
  11. Он начал говорить медленно. – He started speaking slowly.
    говорить – to speak (impf), After verbs that signal beginning (like начать – to start), continuation, or ending an imperfective verb follows (говорить)
  12. Я уже очень устал. Поработаю чуть-чуть и поеду домой. – I’m already very tired. I’ll work a little bit and I’ll go home.
    порабоать – to work (pf), Action of Limited Duration
  13. Ты уже написал статью? Мы очень хотим её прочитать. – Have you written the article already? We’re looking forward to reading it.
    написать – to write (pf), Expected Action – Focus on the completion of the Action
  14. Я слышал что ты путешествовал по России. Покажи мне фотографии пожалуйста! – I heard that you travelled in Russian. Show me pictures please!
    показать – to show (pf), Typical single occasion action – Imperative
  15. Чего ты ждешь? Я очень хочу увидеть фотки из России. Показывай уже!!! – What are you waiting for? I so much want to see the pictures from Russia. Come on, show me the pictures!
    показывать – to show (impf), Imperative expressing Impatience
  16. Когда нам сообщили эту новость, мы запрыгали от радости. – When they told us the news, we started jumping from happiness.
    запрыгать – to jump (pf), Beginning of Action
  17. – Это ты открыл окно опять? – Was it you that opened the window again?
    – Нет, я не открывал. – No, it was not me!
    открыть – to open (pf), открывать – to open (impf), Denial of an action
  18. Таня, ты когда-нибудь покупала эти яблоки? Мне кажется, что они вкусные. – Tanya, have you ever bought these apples? They look tasty.
    покупать – to buy (impf), Simple question about whether something has occurred or not – focus on the action
  19. Он выучил английский за год! Представляешь??? – It took him one year to learn English! Can you imagine that?
    выучить – to learn (impf), Action that happened in a specific amount of time (note the preposition за).
  20. Когда она жила в деревне, она привыкла вставать рано. – When she lived in the village, she used to get out of bed early.
    вставать – to get out of bed (impf), After verbs that denote learning or becoming accustomed (like привыкнуть here) we use an imperfective infinitive (вставать)
  21. У кого ты так хорошо научился играть в шахматы? – Who taught you to play chess so well?
    играть – to play (impf), After verbs that denote learning (like научиться here) we use an imperfective infinitive (играть).
  22. Мне надоело решать эти трудные задачи. – I had enough of solving these difficult problems.
    решать – to solve (impf), A repeated action is implied here.
  23. Я забыл купить тебе подарок ! Извини! – I forgot to get you a present. I’m sorry.
    купить – to buy (pf), single action – one instance
  24. Мы часто встречались раньше, а теперь очень редко потому что живём в разных городах. – We used to meet often in the past, but now we meet very rarely as we live in different cities.
    встречаться – to meet (impf), Repeated Action in the past
  25. Вы прочитали весь рассказ? –  Did you finish reading the whole story?
    прочитать – to read (pf), Focus on the completion of the action
  26. Она открыла дверь, вошла в комнату, и села за стол. – She opened the door, entered the room and sat behind the table.
    открыть – to open (pf), войти – to enter (pf), сесть – to sit (pf), Sequential Actions expressed with perfective verbs
  27. Вам не холодно? Я открою окно. –  You’re not cold? I’ll open the window.
    открыть – to open (pf), Single instance event
  28. Не покупайте этот словарь. Он плохой. – Don’t buy this dictionary. It’s bad.
    покупать – to buy (impf), Negative Imperative takes imperfective verb