Learn Hardcore Russian: Ученик внимательно слушает урок. - The student is listening to the lesson attentively.

Ученик – noun, masculine, singular, nominative. It is the subject of the sentence.
внимательно – adverb, formed from the adjective внимательный (attentive). It modifies the verb, telling us how he listens.
слушает – verb слушать, 3rd person singular, present tense, imperfective aspect. It is the predicate (the main verb).
урок – noun, masculine, singular, accusative. It is the direct object (what he is listening to).

Why is there no word for a or the in this Russian sentence?

Russian has no articles (no words like a/an or the). Whether you translate ученик as a pupil or the pupil depends entirely on context, not on any special word in Russian.

So:

Ученик внимательно слушает урок
can be:
A pupil is listening carefully to the lesson, or
The pupil is listening carefully to the lesson,

depending on what has already been mentioned or is obvious from the situation.

What is the difference between ученик, школьник, and студент?

All three refer to people who study, but they’re used in different contexts:

ученик – a pupil; generally anyone who studies under a teacher, but most commonly a school pupil (elementary/middle/high school).
школьник – literally schoolchild, someone who goes to school (not university). Overlaps a lot with ученик, but emphasizes being a school student.
студент – a student at a university or college (higher education).

So in Ученик внимательно слушает урок, we imagine a school pupil in class, not a university student.

Why is it слушает and not слышит? Don’t both mean something like “hear”?

Russian distinguishes these two very clearly:

слушать – to listen (actively), to pay attention with your ears.
слышать – to hear (passively), to perceive sound.

In this sentence:

Ученик внимательно слушает урок means The pupil is (actively) listening to the lesson, paying attention.
If you said Ученик слышит урок, it would mean The pupil hears the lesson (he is able to hear it), but it does not emphasize attention or effort.

What tense and aspect is слушает, and how would I say “will listen” or “listened”?

слушает is:

Present tense, 3rd person singular
Imperfective aspect (ongoing, repeated, or process-focused action)

Aspect pair:

Imperfective: слушать – to listen (in general, process)
Perfective: послушать – to listen (for a while / as a completed action)

Other forms:

He is listening / he listens – Он слушает (same Russian form for both English meanings)
He listened (process / habitual in the past) – Он слушал
He listened (and we see it as a whole completed event) – Он послушал
He will be listening / will listen (process) – Он будет слушать
He will listen (as a completed act) – Он послушает

What exactly is внимательно, and how is it related to внимательный?

внимательный – adjective: attentive, observant (e.g. внимательный ученик – an attentive pupil).
внимательно – adverb: attentively, carefully (e.g. слушать внимательно – to listen attentively).

Formation pattern (very common in Russian):

Adjective ending in -ый / -ий → remove that and add -о
- тихий → тихо (quiet → quietly)
- быстрый → быстро (fast → quickly)
- внимательный → внимательно (attentive → attentively)

So внимательно is “how” the pupil listens.

Why is the word order Ученик внимательно слушает урок? Can I move the words around?

The neutral, most typical order in Russian is Subject – (Adverb) – Verb – Object, so:

Ученик внимательно слушает урок is very natural and neutral.

Russian allows more flexible word order, but changes of order add emphasis or sound poetic / stylistic. For example:

Ученик слушает урок внимательно – emphasizes внимательно a bit more (how he listens).
Внимательно ученик слушает урок – fronted adverb внимательно for stylistic focus (e.g. in a narrative).
Урок внимательно слушает ученик – unusual order; emphasizes that it is the pupil (not someone else) who is listening to the lesson.

For everyday neutral speech, Ученик внимательно слушает урок is best.

Why is урок in this form? How do I know it’s accusative?

урок here is the direct object of слушает – he listens to what? → to the lesson.

Case:

урок is a masculine inanimate noun.
For such nouns, nominative singular and accusative singular have the same form: урок.

So, formally:

Nominative: урок (e.g. Урок начинается – The lesson is starting.)
Accusative: урок (e.g. слушает урок – listens to the lesson.)

You recognize it as accusative here from its role (object of the verb), not from a visible ending.

How would I say “female pupil” in this sentence? Does the verb change?

The feminine form of ученик is:

ученица – a female pupil.

If you change the subject to feminine, the verb form in the present tense stays exactly the same, because Russian present-tense verb endings do not mark gender:

Ученица внимательно слушает урок. – The (female) pupil is listening carefully to the lesson.

In the past tense, the verb would change for gender:

Ученик внимательно слушал урок. – He listened carefully.
Ученица внимательно слушала урок. – She listened carefully.

How would I say “The pupil is listening to the teacher” instead of “to the lesson”?

You need to replace урок with учитель (teacher) in the accusative case:

Учитель (nominative) → учителя (accusative, masculine animate)
Sentence: Ученик внимательно слушает учителя.
– The pupil is listening attentively to the teacher.

For a female teacher (учительница):

учительница (nominative) → учительницу (accusative)
Ученик внимательно слушает учительницу.
– The pupil is listening attentively to the (female) teacher.

Note: слушать still takes a direct object; no preposition like to is used.

Is слушать урок a fixed expression in Russian? Does it mean anything more than just “listen to the lesson”?

Yes, слушать урок is a very common school-related phrase and often implies paying attention in class, not just physically hearing sounds.

Depending on context, слушать урок can be understood as:

to listen to the lesson,
to follow the lesson,
sometimes almost like to behave and pay attention in class.

So Ученик внимательно слушает урок suggests a good, attentive pupil who is doing what he should in class.

Can I omit ученик and just say Внимательно слушает урок like in Spanish or Italian?

You normally cannot omit a full noun subject in this way in Russian.

Dropping a pronoun subject is fine when it’s clear from context:
- Он внимательно слушает урок. → After we already know we’re talking about “him”, you can drop он and just say Внимательно слушает урок, but that sounds like informal narrative, not a neutral full sentence.
Dropping a noun like ученик and not replacing it with a pronoun usually sounds incomplete, unless it is part of a larger context or a poetic / stylistic device.

As a stand‑alone neutral sentence, you should keep Ученик внимательно слушает урок (or use Он…, Она… if the person is already known from context).

How do I pronounce this sentence correctly? Where is the stress in each word?

Approximate stresses (capital letters show stressed syllables):

Ученик – u‑che‑NIK (учени́к)
внимательно – vni‑MA‑tel‑no (внима́тельно)
слушает – SLU‑sha‑yet (слу́шает)
урок – u‑ROK (уро́к)

Together, spoken naturally:

Учени́к внима́тельно слу́шает уро́к.

All consonants are pronounced clearly, and внимательно should be spoken as one flowing word; be careful not to stress -тель- or the final -но.