Пока мама режет хлеб, я накрываю на стол.

Here пока means while.

So Пока мама режет хлеб, я накрываю на стол means While mom is cutting bread, I am setting the table.

A useful thing to know is that пока can mean different things in other contexts, for example:

• for now / for the time being
• until
• bye in informal speech

But in this sentence, with a full clause after it, it means while.

Because Пока мама режет хлеб is a subordinate clause, and я накрываю на стол is the main clause.

Russian normally separates a subordinate clause from the main clause with a comma:

• Пока мама режет хлеб, я накрываю на стол.
• Я накрываю на стол, пока мама режет хлеб.

Both need a comma.

Russian uses the present tense here because the sentence describes two actions happening at the same time.

In English, you would often use the present continuous:

• mom is cutting
• I am setting

But Russian does not need a special continuous form. The ordinary present tense can express:

• a general/habitual action
• an action happening right now
• an ongoing background action

So режет and накрываю can naturally mean is cutting and am setting here.

Because мама is the subject of режет.

It is the person doing the action, so it is in the nominative case.

• мама режет = mom cuts / is cutting

If маму were used, that would be accusative, which would normally mean mom is the object, not the subject.

Хлеб is the direct object of режет, so it is in the accusative case.

But for many masculine inanimate nouns, the accusative singular is identical to the nominative singular.

So:

• nominative: хлеб
• accusative: хлеб

The case is still accusative, but the form happens to look the same.

The infinitive is резать = to cut, but Russian verbs change form when they are conjugated.

Present-tense forms of резать are:

• я режу
• ты режешь
• он / она режет
• мы режем
• вы режете
• они режут

So мама режет means mom cuts / is cutting.

Notice that the stem changes from рез- to реж- in these forms. This kind of stem alternation is common in Russian and just has to be learned with the verb.

It means I am setting the table.

This is a fixed Russian expression:

• накрывать на стол = to set the table
• накрыть на стол = to set the table in the perfective sense, focusing on completion

It does not mean literally to cover onto the table in normal translation. It is best learned as a whole expression.

Because the expression is накрывать на стол, and it uses на with the accusative: стол.

A helpful general rule is:

• на стол = onto the table or movement/result toward the table
• на столе = on the table as a location

Compare:

• Кладу тарелку на стол = I put the plate onto the table
• Тарелка стоит на столе = The plate is on the table

In накрывать на стол, Russian uses the idea of putting things onto the table, so на стол is natural.

Because the sentence focuses on the actions as ongoing processes happening at the same time.

• режет comes from резать — imperfective
• накрываю comes from накрывать — imperfective

Imperfective is used here because the speaker is not emphasizing completion. The meaning is more like:

• while mom is in the process of cutting bread
• I am in the process of setting the table

A perfective verb would not work the same way here, especially because Russian perfective verbs do not have a true present tense. Their present-looking forms usually refer to the future.

Yes, very often.

Russian frequently leaves out subject pronouns when they are clear from the verb ending. So you could say:

• Пока мама режет хлеб, накрываю на стол.

That is grammatically possible, because накрываю already tells you the subject is I.

However, я is often kept for clarity, contrast, or emphasis. In this sentence, я can help highlight the division of roles:

• mom is cutting bread
• I am setting the table

Yes, Russian word order is fairly flexible.

You can also say:

• Я накрываю на стол, пока мама режет хлеб.

The basic meaning stays the same.

The version with пока first makes the time relationship feel more foregrounded: while mom is cutting bread...

Russian word order often changes emphasis, information flow, or style rather than the core meaning.

Because Russian does not have articles.

So мама, хлеб, and стол do not have separate words corresponding to the or a. The listener understands from context whether the meaning is:

• mom / the mom
• bread / the bread
• the table / a table

English needs articles, but Russian normally does not. Context does the work instead.