Learn Hardcore Russian: Я успел сделать домашнее задание вечером. - I managed to do the homework in the evening.

So Я успел сделать домашнее задание вечером means not just “I did my homework in the evening”, but specifically “I *managed to do my homework in the evening (before some deadline / before it was too late).”*

There is an implied time limit, pressure, or risk of not finishing, and the sentence says you succeeded within that time.

Why is it успел and not something else? What if a woman is speaking?

In Russian, past tense verbs agree with the gender and number of the subject.

The infinitive is успеть. Its past tense forms are:

я / он успел – masculine singular
я / она успела – feminine singular
оно успело – neuter singular
мы / вы / они успели – plural (any gender mix)

So:

A man would say: Я успел сделать домашнее задание вечером.
A woman would say: Я успела сделать домашнее задание вечером.

The rest of the sentence stays the same; only the verb ending changes.

Why do we say успел сделать, and not just сделал?

Both are possible, but they don’t mean the same thing:

Я сделал домашнее задание вечером.
→ I did my homework in the evening.
Neutral statement of fact: the homework was done; no special focus on time pressure.
Я успел сделать домашнее задание вечером.
→ I managed to do my homework in the evening (in time).
Emphasizes that there was some time constraint or risk of not doing it (maybe you were busy, tired, had to go somewhere, etc.), and in spite of that, you succeeded.

So успел сделать = managed to do / got it done in time, while сделал = did / completed (without that nuance).

Why is сделать in the infinitive form, not in the past tense (сделал)?

In успел сделать, the main (finite) verb is успел, and сделать is a dependent infinitive:

успеть + infinitive = to manage to do something, to have time to do something

Pattern:

Я успел сделать… – I managed to do…
Я успел прочитать… – I managed to read…
Я успел написать… – I managed to write…

If you changed сделать to сделал, you’d get two finite past-tense verbs in a row, which doesn’t work as a single clause in Russian. You’d need a conjunction and a different structure, e.g.:

Я успел и сделал домашнее задание.
(I was in time and (then) did my homework.) – different meaning and structure.

Why is it сделать (perfective) and not делать (imperfective)?

Russian aspect is important here:

делать – imperfective: to do (ongoing, repeated, process)
сделать – perfective: to do / to complete (single, finished action)

With успеть, you almost always use a perfective infinitive when you mean that you completed the action in time:

Я успел сделать домашнее задание.
→ I managed to finish my homework (completed).

If you said:

Я успел делать домашнее задание.

it would sound strange in most contexts, and if it’s used at all, it would suggest something like “I had time to be doing homework (as an ongoing activity)”, not necessarily finishing it. The natural way to say “I managed to finish my homework” is with сделать, the perfective form.

What case is домашнее задание in, and why does it look like the dictionary form?

Домашнее задание is the direct object of сделать, so it is in the accusative case.

The noun задание is neuter singular. For neuter, inanimate nouns, the nominative and accusative forms are identical:

Nominative: домашнее задание – homework (as a subject)
Accusative: сделать домашнее задание – to do homework (as an object)

So it looks like the dictionary form (nominative), but grammatically here it is accusative.

Form breakdown:

домашнее – neuter singular long-form adjective (from домашний / домашняя / домашнее)
задание – neuter singular noun

Why is “homework” translated as домашнее задание? Can I say something else?

Домашнее задание is the standard school term for “homework” (an assignment given by a teacher).

Typical options:

домашнее задание – homework, assignment (most neutral/standard)
домашние задания – homework assignments (plural, several tasks)
домашка (colloquial/slang) – homework (very informal: Я сделал домашку.)
уроки (colloquial) – literally “lessons,” but in some regions/families used to mean homework: делать уроки = do homework

Домашняя работа is usually not school homework; it more often means:

home-based work (for a job)
tasks/work done at home, like housework (but then context changes)

So for normal school/university homework, домашнее задание is the safest, most correct choice.

Why is there no моё (“my”) in домашнее задание? Would моё домашнее задание be wrong?

Моё домашнее задание is grammatically correct, but in this context it’s usually not necessary.

In Russian, possessive pronouns (мой, твой, наш, ваш, его, её, их) are often omitted when the owner is obvious from context, especially with:

body parts: Я мыл руки. (I washed (my) hands.)
family members: Я позвонил маме. (I called (my) mom.)
clearly personal things: Я сделал домашнее задание. (It’s naturally “my homework.”)

Adding моё:

Я успел сделать моё домашнее задание вечером.

would emphasize “my own homework, not someone else’s” or sound a bit redundant in a neutral context. It’s only used when you really want to contrast whose homework it is.

Why do we say вечером and not в вечер for “in the evening”?

Russian often uses the instrumental case of time-nouns as an adverbial to express “at / in (that part of the day)”:

утром – in the morning (from утро)
днём – in the daytime / during the day (from день)
вечером – in the evening (from вечер)
ночью – at night (from ночь; the instrumental and other forms merge here)

So вечером literally is the instrumental singular form of вечер, and the whole phrase means “in the evening”.

Using в вечер is generally wrong in this meaning in modern standard Russian. You might see something like в этот вечер (on this evening, that evening), but not bare в вечер for “in the evening” in general.

Can the word вечером be placed elsewhere in the sentence? Does the word order change the meaning?

Yes, вечером is quite flexible in position. All of these are grammatically correct:

Я успел сделать домашнее задание вечером.
– Neutral, very common. Focus is mostly on the fact that you managed to do it, with when (in the evening) added at the end.
Я вечером успел сделать домашнее задание.
– Slightly stronger focus on when you managed to do it (in the evening rather than at some other time).
Вечером я успел сделать домашнее задание.
– Strongest emphasis on “in the evening”, often in contrast to another time:
Вечером я успел сделать домашнее задание, а утром нет.
(In the evening I managed to do my homework, but in the morning I didn’t.)

The basic meaning doesn’t change, but word order shifts the emphasis (what is new/contrasted information). Russian word order is more flexible than English for such adverbials.

Can I replace успел with смог? What is the difference between успеть and смочь?

You can say:

Я смог сделать домашнее задание вечером.
→ I was able to do my homework in the evening.

But успел and смог have different main ideas:

успеть – focuses on time and being in time:
did you manage before a deadline / before it was too late?
смочь – focuses on ability or overcoming difficulty:
did you have the ability/strength/opportunity to do it?

So:

Я успел сделать домашнее задание вечером.
→ There was a time limit (maybe you were busy, had other plans), and you finished it in time.
Я смог сделать домашнее задание вечером.
→ There was some difficulty or obstacle (tiredness, lack of understanding, no internet, etc.), and you managed to overcome it and do the homework.

In many contexts they can both be used, but the nuance is different: успел = “in time”, смог = “was able to.”

What is the imperfective partner of успеть, and how is it used compared to успеть?

The imperfective partner of успеть is успевать.

успевать – imperfective (process, habit, repeated actions)
успеть – perfective (single completed event, result)

Compare:

Я успеваю делать домашнее задание вечером.
– I (usually) manage to do my homework in the evening.
Describes a regular pattern or general ability.
Я успел сделать домашнее задание вечером.
– I (this time) managed to do my homework in the evening.
Describes one specific occasion and its result.

So your sentence uses успел because it talks about a specific instance in the past, with a completed result.