В пятницу у нас будет зачёт по истории, поэтому я сегодня повторяю даты.

Пятницу is in the accusative singular.

After в, Russian often uses the accusative to mean on / at a specific time, especially with days of the week:

• в понедельник — on Monday
• в среду — on Wednesday
• в пятницу — on Friday

The basic form is пятница. Since it is a feminine noun ending in -а, the accusative singular changes -а to -у:

• пятница → пятницу

So в пятницу means on Friday.

Because у нас будет... is the natural Russian way to say we have / we will have in many contexts.

Literally, у нас будет зачёт is something like at us there will be a test. In normal English, we just say we’ll have a test.

Russian usually avoids using a direct equivalent of to have in this kind of sentence. Instead, it uses:

• у + genitive for the person(s)
• a form of быть for existence
• the thing/event itself

So:

• у меня есть книга — I have a book
• у нас будет зачёт — we will have a test / there will be a test for us

Мы будем иметь зачёт is grammatically possible in a very literal sense, but it sounds unnatural here.

Here у нас means something like for us, in our group/class, or simply we have.

It does not function as the grammatical subject. It is part of the Russian possession/existence construction.

Depending on context, у нас будет зачёт could mean:

• our class has a test
• we have a test
• there will be a test for us

So у нас is broader than just a plain English we.

Because the grammatical subject is зачёт, which is singular.

• зачёт — singular masculine noun
• therefore: будет зачёт

Even though у нас refers to more than one person, у нас is not the subject. The sentence is built around the idea there will be a test.

Compare:

• У нас будет зачёт — We will have a test
• У нас будут экзамены — We will have exams

In the second sentence, экзамены is plural, so the verb becomes будут.

Not exactly.

A зачёт is a specific type of assessment in Russian-speaking educational systems. It is often a pass/fail credit, not always a full graded exam.

Very roughly:

• экзамен — exam
• зачёт — pass/fail test, credit, course check-off

Sometimes a зачёт can still involve answering questions or being tested, but the result is usually more like passed / not passed rather than a detailed grade.

So in translation, depending on context, it might be rendered as:

• test
• credit
• pass/fail assessment

Also, remember the spelling: зачёт has ё.

After по in the sense of in / on a subject, Russian uses the dative case.

So:

• история — history
• по истории — in history / on history

This is a very common pattern for school subjects:

• по математике — in math
• по физике — in physics
• по русскому языку — in Russian
• по истории — in history

For история, the dative singular form is истории.

Because поэтому here connects two clauses:

• В пятницу у нас будет зачёт по истории
• поэтому я сегодня повторяю даты

It means therefore / so / that’s why, and in this sentence it introduces the result or consequence of the first clause.

So the comma works much like in English:

• We have a test on Friday, so I’m reviewing dates today.

Russian punctuation is often a bit stricter than English here, and the comma is expected.

No. They are related in meaning, but they do different jobs.

• поэтому = therefore / so / that’s why
• потому что = because

Compare:

• В пятницу будет зачёт, поэтому я повторяю даты.
  On Friday there will be a test, so I’m reviewing dates.

• Я повторяю даты, потому что в пятницу будет зачёт.
  I’m reviewing dates because there will be a test on Friday.

So поэтому introduces the result, while потому что introduces the reason.

Because the speaker is talking about what they are doing today, right now or during today.

• будет зачёт — future event
• сегодня повторяю — present action happening today

This is completely normal in Russian.

The sentence means: the test is on Friday, so today I am reviewing dates.

Russian present tense often covers both:

• actions happening right now
• actions happening during the current period

So я сегодня повторяю даты can mean I’m reviewing dates today even if the action is not happening at this exact second.

Yes, the basic meaning of повторять is to repeat, but in study contexts it very often means to review.

So:

• повторять слова — review/repeat words
• повторять правила — review rules
• повторять даты — review dates

This is a very common Russian way to talk about going over material again before a test or exam.

So here повторяю даты is best understood as I’m reviewing dates, not mechanically saying dates aloud over and over.

This is about aspect.

• повторяю — imperfective
• повторю — perfective

The imperfective повторяю is used because the speaker is describing an ongoing process: they are in the middle of reviewing.

The perfective повторю would mean something more like I will review / I’ll review and finish reviewing.

Compare:

• Я сегодня повторяю даты. — I’m reviewing dates today.
• Я сегодня повторю даты. — I’ll review the dates today. / I’ll go over the dates today.

Both can be possible in different contexts, but повторяю focuses on the activity itself, while повторю points more toward completing it.

Даты is the accusative plural, because it is the direct object of повторяю.

The dictionary form is:

• дата — date

Plural nominative:

• даты — dates

Since даты is an inanimate noun, the accusative plural looks the same as the nominative plural:

• nominative plural: даты
• accusative plural: даты

So in the sentence:

• я повторяю даты — I’m reviewing dates

Yes, Russian word order is flexible.

The sentence has:

• поэтому я сегодня повторяю даты

This is a natural order, with сегодня smoothly placed before the verb.

But Russian could also say:

• поэтому сегодня я повторяю даты
• поэтому я повторяю сегодня даты
• поэтому даты я сегодня повторяю

These all shift emphasis a little.

The version in your sentence is neutral and natural. It emphasizes the simple idea: so I’m reviewing dates today.

In Russian, word order often reflects focus, contrast, or style, not just grammar.

Yes, you should.

The word is зачёт, not зачет in pronunciation. The stress is on -чёт:

• зачёт

In printed Russian, ё is often replaced by е, but learners should still know the real pronunciation. If you see зачет in a text, it is usually still pronounced зачёт.

That is important because ё always carries stress.

A helpful stress guide is:

• в пя́тницу
• у нас бу́дет зачёт
• по исто́рии
• поэ́тому
• я сего́дня повторя́ю да́ты

A few especially useful ones to remember:

• пя́тница
• зачёт
• исто́рия
• сего́дня
• повторя́ю
• да́та

Stress is very important in Russian, because it is not always predictable from spelling.