Učitelka říká, že v batohu mají být vždycky sešit, tužka i guma.

Učitelka means female teacher. Czech usually marks gender in job nouns, so:

• učitel = male teacher
• učitelka = female teacher

Because the sentence starts with Učitelka říká..., it specifically tells you the speaker is a woman.

In Czech, a comma is normally used before že when it introduces a subordinate clause.

So:

• Učitelka říká = The teacher says
• že... = that...

The comma works much like in English The teacher says that..., except Czech punctuation requires it here.

Because v here means in, and when it expresses location, the noun after it usually goes into the locative case.

• basic form: batoh = backpack
• after v for location: v batohu = in the backpack

So this is not a random ending change; it is required by the preposition and the meaning of location.

Mají být here means something like are supposed to be, should be, or are meant to be.

Compare:

• jsou v batohu = they are in the backpack
• mají být v batohu = they are supposed to be in the backpack

So the teacher is not just describing reality; she is stating a rule or expectation.

This is softer or more instructional than a plain statement, and often a bit less blunt than musí být (must be).

Because together they form a compound subject: sešit, tužka i guma.

Even though each item is singular by itself:

• sešit = notebook
• tužka = pencil
• guma = eraser/rubber

the whole group is plural in meaning: a notebook, a pencil, and an eraser.

So the verb agrees with the whole group, which is why you get mají být and not má být.

Because the sentence means that the backpack should contain one notebook, one pencil, and one eraser as standard items.

In Czech, when listing required items like this, it is very normal to use singular nouns:

• sešit
• tužka
• guma

This does not mean only one item can ever exist in the world; it just means each listed school item is named in its basic singular form.

They are in the nominative case.

That may feel surprising at first, because in English learners often look for an object after the verb. But here these nouns are not direct objects. They are the things that are supposed to be in the backpack, so they function as the subject of mají být.

A helpful way to see it is:

• v batohu mají být sešit, tužka i guma
• literally: in the backpack are supposed to be a notebook, a pencil, and an eraser

So the listed nouns are nominative subjects placed after the verb.

Here i means something like and also, as well as, or simply and with a slight emphasis on the last item.

So:

• sešit, tužka i guma

means:

• a notebook, a pencil, and an eraser
• or more literally: a notebook, a pencil, and also an eraser

You could often replace i with a in a simple list, but i can give a small sense of including that too.

Czech word order is much more flexible than English word order. The sentence could be rearranged in other ways without changing the core meaning much.

This version:

• Učitelka říká, že v batohu mají být vždycky sešit, tužka i guma.

puts v batohu early, so the backpack is introduced as the setting first. That is very natural in Czech.

A more English-like order would be:

• Učitelka říká, že sešit, tužka i guma mají být vždycky v batohu.

Both are grammatical. Czech often moves elements around for emphasis, topic, and information flow.

Vždycky means always.

In this sentence it means these items should always be in the backpack, not just sometimes.

Czech adverbs like vždycky can often move around:

• v batohu mají být vždycky...
• vždycky mají být v batohu...
• mají být vždycky v batohu...

The meaning stays very similar, though the emphasis can shift slightly.

Because Czech has no articles.

So:

• sešit can mean a notebook or the notebook
• tužka can mean a pencil or the pencil
• guma can mean an eraser or the eraser

The exact meaning depends on context. In this sentence, English naturally translates them as a notebook, a pencil, and an eraser.

Yes, depending on context, mají být can come close to should be, are supposed to be, or even must be.

But the most neutral explanation here is:

• are supposed to be
• should be

If the teacher wanted to sound more forceful, Czech might use:

• musí být = must be

So mají být usually sounds like an expectation, instruction, or rule rather than the strongest possible command.