Na końcu tego zdania powinien być wykrzyknik.

Because na końcu describes a location: at the end.

In Polish, na can take different cases depending on meaning:

• na + locative = location
  
  • na końcu = at the end
• na + accusative = movement toward a place / result
  
  • na koniec = for the end / at the end / finally, often more like a time expression or destination

So here the sentence is talking about where the exclamation mark should be, not movement toward the end.

Because after na in the meaning of location, the noun goes into the locative case.

The basic form is:

• koniec = end

Its locative singular form is:

• końcu

So:

• na końcu = at the end

This is just the case form required by the preposition and meaning.

Because Polish expresses of this sentence using the genitive case.

The phrase is built like this:

• koniec zdania = the end of the sentence
• koniec tego zdania = the end of this sentence

Here:

• zdanie → zdania = genitive singular
• to / ten-type demonstrative → tego = genitive singular form used with zdania

So tego zdania literally works like of this sentence.

Because it agrees with wykrzyknik, which is a masculine singular noun.

In this sentence, wykrzyknik is the thing that should be somewhere, so powinien matches it:

• wykrzyknik — masculine singular
• powinien — masculine singular

If the subject were feminine or neuter, the form would change:

• kropka powinna być... = the period/full stop should be...
• słowo powinno być... = the word should be...

Because powinien is a modal-like word meaning should, and it usually goes with an infinitive that tells you what should happen.

Here:

• powinien być = should be

So the structure is:

• wykrzyknik powinien być na końcu...
• literally: the exclamation mark should be at the end...

Without być, the sentence would feel incomplete, because you would be missing the main action/state: be.

Because wykrzyknik is the subject of the clause, so it stays in the nominative case.

The core structure is:

• wykrzyknik powinien być = the exclamation mark should be

Even though English often feels like the important thing here is the location, grammatically in Polish wykrzyknik is still the subject.

So:

• wykrzyknik = nominative, because it is the thing being talked about
• na końcu tego zdania = a prepositional phrase telling you where

Polish word order is much more flexible than English word order.

English strongly prefers:

• An exclamation mark should be at the end of this sentence.

Polish can say that too:

• Wykrzyknik powinien być na końcu tego zdania.

But the version you have:

• Na końcu tego zdania powinien być wykrzyknik.

puts the location first, which gives it a slightly different emphasis. It sounds a bit like:

• At the end of this sentence, there should be an exclamation mark.

This kind of ordering is very natural in Polish when the speaker wants to foreground the setting or location and leave the key item until the end.

Yes. That is also correct.

Both versions are grammatical:

• Na końcu tego zdania powinien być wykrzyknik.
• Wykrzyknik powinien być na końcu tego zdania.

The difference is mainly emphasis:

• Na końcu tego zdania... focuses first on the place
• Wykrzyknik powinien być... focuses first on the exclamation mark

So this is more about style and information structure than about right vs. wrong.

Because Polish has no articles.

So Polish does not have separate words corresponding directly to English a/an and the.

Whether something is definite or indefinite is understood from context, word order, or extra words if needed.

So wykrzyknik can mean:

• an exclamation mark
• the exclamation mark

In this sentence, English would normally use an or the, but Polish simply does not need one.

Yes. In this sentence, wykrzyknik means exclamation mark.

It is a common Polish word for the punctuation sign !

You may also see:

• znak wykrzyknienia = a more formal/literal term, also exclamation mark

So in everyday use, wykrzyknik is completely normal here.

Not exactly.

Być is roughly pronounced like bihch with a very short central vowel and a soft final consonant. The y in Polish is not the same as English i in bit, though that is a rough beginner approximation.

Also:

• ć is a soft consonant, something like a very soft ch/tch sound

So if you are a beginner, an approximate pronunciation is fine, but it is not identical to any common English word.

Because nothing in the sentence requires one.

Na końcu tego zdania is just a normal prepositional phrase at the beginning of the sentence, and Polish does not automatically put a comma after such phrases.

So:

• Na końcu tego zdania powinien być wykrzyknik. ✅

A comma would usually be incorrect here unless the writer wanted some very unusual pause for stylistic effect.