A guide on "X is Y" and "This is Y" constructions

It comes as no surprise that one of the most asked questions in the earlier stages of the course is about the "to" + Nominative vs „być” + Instrumental in sentences which I call „X is Y”. I’ll try to write a comprehensive guide here, so everything about this topic could be in one place.

So, the base for the translation is an English sentence that has an “X is Y” (or “X are Y”) construction.


One of the most common options is when both X and Y are noun phrases. Note – not necessarily nouns (“sandwich”), but noun phrases (“a big sandwich”). If that is the case, we have two ways that we can use to translate the sentence into Polish.

  • Option one is: X in Nominative + a form of ‘być’ (conjugation here) + Y in Instrumental.

  • Option two is: X in Nominative + 'to' + Y in Nominative.

You know the word ‘to’ as a neuter personal pronoun, but it is not the function that is serves here. In this context it will always be ‘to’ and won't change at all.

So on a simple example of “A dog is an animal.”:

  • 1) Pies jest zwierzęciem.

  • 2) Pies to zwierzę.

In plural (“Dogs are animals.”):

  • 1) Psy są zwierzętami.
  • 2) Psy to zwierzęta.

And now, an example with not just nouns, but noun phrases. Remember that not only adjectives can create noun phrases, but also for example articles, or pronouns like ‘this’. If you're not into linguistics enough to be sure that you know enough about noun phrases, read here.

So our example here will be:

This green piece of furniture is a wooden table.

  • 1) Ten zielony mebel jest drewnianym stołem.

  • 2) Ten zielony mebel to drewniany stół.

If we make it plural: These green pieces of furniture are wooden tables, we arrive at:

  • 1) Te zielone meble są drewnianymi stołami.

  • 2) Te zielone meble to drewniane stoły.

If the Y part is negated, we add „nie” in Polish. But where to add it? Well, it depends which option we are using. In the option number one, we negate the verb “to be”. So if for some reason we tried to claim that a dog is not in fact an animal, then it would be:

  • Pies nie jest zwierzęciem.

In option number two, we negate the Y part. So the same sentence would be:

  • Pies to nie zwierzę.


Remember that it is important which part we will make "Y" and put into Instrumental. You can arrive at a sentence that is grammatically correct, but won't make sense semantically. Let me show it on geometry:

  • Każdy kwadrat jest prostokątem, ale nie każdy prostokąt jest kwadratem. (Every square is a rectangle, but not every rectangle is a square.)

  • "Kot jest zwierzęciem" (A cat is an animal) is okay, but "Zwierzę jest kotem" (An animal is a cat) is wrong. Not grammatically wrong, but semantically wrong. A specific animal can be a cat, but a totally general 'an animal' cannot, only some animals are cats.

  • "Paweł jest lekarzem" (Paul is a doctor) is obviously correct, but "Lekarz jest Pawłem" (A doctor is 'a' Paul) is really weird.

Sometimes the left noun phrase can be put in Instrumental, and the right be in Nominative (let's treat is as "Y is X"), but as you are learning, it's probably better to stick to the basic way, as this shows a change of focus. Anyway, the example that made me realize it needs adding to this guide was:

  • "Twoim zadaniem jest znaleźć wyjście." (Your task is to find an exit.)

Let's translate the Y part not as an infinitive, but as a gerund: "Your task is finding an exit". We now have four potential options to say that, depending on which part we want to stress: what is the task, or whose the task is.

The first two options will focus on 'what':

  • "Twoim zadaniem jest znalezienie wyjścia"

  • "Twoje zadanie to znalezienie wyjścia"

The other two focus on 'whose', and that it is 'a task':

  • "Znalezienie wyjścia jest twoim zadaniem"

  • "Znalezienie wyjścia to twoje zadanie"

Still, whether it's on the left side of the sentence or on the right, it's only the task that is put into Instrumental. So I think I'd say that it's the matter of what defines what. A definition of 'a cat', although a very simplified one, is that it is in fact 'an animal'. 'An animal' cannot however be defined as 'a cat'. Your task can be defined (precised) by saying that it is "to find the exit". It's hard, at least in Polish, to define "finding the exit" as being "your task". That's why only the task part can be in Instrumental, even if it's at the beginning of the sentence.

But there are sentences, when depending on the focus either of the noun phrases could be made Instrumental. Compare:

  • Mężczyzna jest mordercą (The man is a murderer)

So 'the man', therefore some man that was already mentioned (more probably "this man" = "ten mężczyzna") is a murderer.

  • Morderca jest mężczyzną. (The murderer is a man)

There is a murderer, but so far the only thing we know is that it's a man. This sentence could be possibly changed to "Mordercą jest mężczyzna", but it's better to focus on the more basic constructions now.


Okay, so I hope that covers the most popular option. Now, another common thing is when X is a personal pronoun (I, you, they etc.) The only option that will sound natural then is option number one. DO NOT try to use option two, with ‘to’, here.

  • I am a man. = Ja jestem mężczyzną.

  • She is a beautiful woman. = Ona jest piękną kobietą.

  • They are her friends. = Oni są jej przyjaciółmi or One są jej przyjaciółkami.

(If the oni/one confuses you, see here and look for the distinction between masculine personal and not masculine personal.)

As the form of 'być' already implies the person, we usually omit the personal pronoun. It's probably 'the hardest' to omit it with 3rd person, as gender may not be obvious without it.


The main option for introducing yourself is literally "I call myself Y" = "Nazywam się Y", but there's also a possibility of using simple "I am". The Polish version will be somewhere between options one and two, actually. It has to be:

Personal pronoun + a form of 'być' + the name/surname in Nominative.

Yes, Nominative. Being "Mary" doesn't define you, you are "Mary". Being "a doctor" kind of defines you, so it goes into Instrumental. But here it has to be Nominative.**

  • Jestem Marek. = I'm Marek.

  • Jesteś Maria Nowak, prawda? = You're Maria Nowak, right?

  • Jesteśmy Nowakowie = We are the Nowaks (the Nowak family)

  • Jesteście Burdonowie, prawda? = You are the Burdons, right? (the Burdon family)

With 3rd person, both English and Polish should rather use "This is/These are" and not "He/She is/They are". Therefore:

  • To jest Tomasz. = This is Tomasz.

  • To są Kowalscy. = These are the Kowalskis (the Kowalski family)

** There's an exception in a weird construction such as "Because Mary was Mary, she obviously got angry" (Because of her character and because she's always 'herself', she got angry because she's a nervous person). You could use "Ponieważ Maria była Marią" here. The first "Mary" could probably even be simple "she" (and "ona" or omited in Polish). But that's completely on the side, as it's quite an unusual usage.


Another situation will be, when X is a noun phrase (or a personal pronoun), but Y is an adjective. You should then use a 'mixed structure', just like in Part 2,5:

X in Nominative + a form of 'być' + the adjective in Nominative.

  • “This table is heavy” will translate as “Ten stół jest ciężki”.

  • “The women are beautiful” will translate to “Kobiety są piękne”.

  • “He is intelligent” will translate to “On jest inteligentny."

If negated, as this is option number one, ‘nie’ will be put before the form of ‘być’.

The only exception to this, that I found so far, is when you speak about your favourite colours. One could argue that the adjective denoting the colour is treated as a noun, therefore “My favourite colour is red” will be translated using option number two as:

  • “Mój ulubiony kolor to czerwony”.

It can be reversed to “Red is my favourite colour” and will result with:

  • “Czerwony to mój ulubiony kolor”.

Option number one could be used with the second sentence (“Czerwony jest moim ulubionym kolorem”) as Y is a noun phrase here, but not in the first one, where Y is an adjective. The negations would work the same way that I mentioned before.


Another thing that sometimes causes problems is translating a very simple phrase built as “This is Y”.

As you can see, “this” doesn’t serve as a determiner here (like in “this boy”, “this animal”), but as a pronoun, which is in fact the subject of the sentence. In Polish, it will be translated as “To” – and of course, being the subject, “To” won’t change at all, no matter what gender we use, or whether it’s singular or plural.

It also doesn’t matter whether the English original sentence had “This/That/These/Those” – all of them will translate as “To”.

So showing this on some examples:

  • This is a dog. = To jest pies.

  • That is a good idea! = To jest dobry pomysł!

  • These are very fast cars. = To są bardzo szybkie samochody.

  • Those are red books = To są czerwone książki.

In such sentences, the form of ‘być’ is actually optional, you can omit it. So is the case with the 3rd person options for names/surnames. In my opinion sometimes the sentence can look a bit weird without the 'być', if it's very short (To pies), but I have no problem at all with "To dobry pomysł!"

And of course in negation, ‘nie’ will go before the form of ‘być’, even if it’s actually omitted (“To nie (jest) pies.”)


If you have a construction “This is Y” or “That is Y” and Y is an adjective, in Polish you obviously need “To jest”, and the adjective is neuter singular.

  • This is interesting. = To (jest) interesujące/ciekawe.

  • That is just stupid. = To (jest) po prostu głupie.

It is not obligatory to use “jest” and in fact, sentences with some adjectives seem more natural with “jest”, and some without it. You cannot just use “Jest” without “To” here.

If Y is an adverb, then the sentence is in fact subjectless in Polish. In English, it should probably start with “It”. This is then some kind of general “it”, which doesn’t really mean anything specific.

  • It is cold. = Jest zimno.

  • Na dworze jest gorąco. = It is hot outside.

  • W naszej szkole jest nudno. = It is boring in our school.

There isn’t any “to” in Polish, as there is no real subject.


I saw problems arrising when X was an adverb, at least an adverb of time (today, yesterday, tomorrow, etc.). Such a situation calls for a mixed construction, similar to the one in Part 2.5 with names.

X (Adverb) + a form of 'być' + Y in Nominative.

The only form of 'być' that makes sense here is 3rd person, so either singular "jest" or plural "są".

  • Dzisiaj jest niedziela. (Today is Sunday.)

  • W przyszłym miesiącu są egzaminy. (In the next month, there are exams.)

  • W poniedziałek są urodziny Moniki. (On Monday there's Monika's birthday).

  • Tu jest Polska, tu się pije! (Here is Poland, one drinks here!)

  • Tam jest jaskinia. (There is a cave there.)


The last thing that comes to my mind, that I saw on Duolingo once, is the kind of a sentence which is more of a wordplay than a real description of something. So for example “A good sofa is a comfortable sofa”, or “A good enemy is a dead enemy”.

Such a situation calls for the option number two, number one would sound really weird here. Therefore the translations will be, respectively:

  • Dobra sofa to wygodna sofa.

  • Dobry wróg to martwy wróg.

Well, I guess that’s it. If you notice something that I missed, or maybe some mistake that I made, please don’t hesitate to comment and I will add/correct it.

June 28, 2016


Dziękuję! That's a lot of effort! Deserves a lingot and an upvote from me!

October 8, 2016

Wow, this is thorough, bookmarked it already. Thank you for taking the time to explain all possible scenarios! :)

June 29, 2016

Thanks for that brief explanation! :-) It's very helpful and informative; I need to reread it and absorb it in segments. My little brain can't take it all in at once.

March 31, 2017

Thanks! Just troubleshooting - part 4.5 refers to "This is Y" when Y is an adverb. The structures given in Polish are (adverb = adjective), and in English are (It = adjective adverb).

I was briefly confused, as neither language shows a "This is Y, where Y is an adverb" structure. I got there, but I wonder if this could be clearer.

Thanks again for your extensive help across the message boards!

December 22, 2018
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You're welcome :) I renamed the section to just "PART FOUR AND A HALF: WHEN Y IS AN ADJECTIVE/ADVERB", deleting the confusing (wrong?) part, I hope it's enough :)

December 27, 2018

Thank you so much. Could you also explain why one says "Tego nie było" vs. "To nie było"? I think I remember a sentence here in Duo that was "Tego nie było w umowie" and I wondered why it wasn't "To nie było w umowie."

June 30, 2016
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I'd say that it's kinda similar to how strange is the Polish version of "I'm not at home" = "Nie ma mnie w domu", literally "There is not (or even There has not) me at home". That construction uses Genitive because of the questions you'd use in Polish (Kogo nie ma w domu? Czego nie ma w domu?), and it's similar here, it's just "an agreement" instead of "home". I think the second option, with 'to', is therefore simply not correct.

July 1, 2016

I would say that use of Genitive for negation is obligatory in Polish. It is the base role of Genitive. In Polish Genitive is "Dopelniacz" - from verb dopełniać - "tu fulfill" or "to complete"). The base question for Genitive is: kogo? czego? [nie ma] - "Who or what is missing?"

September 15, 2016
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Genitive in Polish nas many roles:

October 16, 2016

I've recently noticed the part 3b or 4b is missing.

<h1>"this is x" when x is adjective. "To jest" + nominative neuter singular adjective. you cannot omit "jest"</h1>

example: to jest ładne= this is pretty to jest ciekawe

October 11, 2016
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Finally added that as Part 4,5 - but I can't really agree with the claim that one cannot omit "jest". "To ciekawe." is a valid sentence to me.

November 4, 2016

"to ciekawe" is a set phrase. Any other sentence feels weird "to brzydkie" "to różowe" "to drewniane"

November 4, 2016
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That's why I wrote that sometimes it feels good with 'jest', sometimes not... the number of such 'set phrases' is definitely greater. Hard to find a rule :/

November 5, 2016

A very good and clear survey for us to learn, but why is Monika's birthday plural?

April 30, 2017
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"urodziny" is plurale tantum, it's always plural. There is no other way to say that, unless you want to go with "dzień urodzin" (the day of the birthday?), which seems acceptable - but why use it?

April 30, 2017

Perhaps it's like 'her birthday celebrations'.

Some other festival names are also plural, e.g. 'Saturnalia'.

August 30, 2017

Thanks for taking the time to write that out!

May 4, 2017

Excellent! Excellent! One lingot for you, Jellei!

June 2, 2017

This is so incredibly helpful!!!

January 11, 2019

I apologize if it's already been covered, but I've read this post at least twenty times so if it has been I'm obviously not getting it.

In Part One: When Both X and Y are Noun Phrases you've explained both constructions (very clearly, I might add), but I don't see anything on when to use which. Are they always completely interchangeable, or is one sometimes better than the other? Are there any nuances in meaning?


June 28, 2017
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I'd say that if the noun phrase X denotes some person (Like "My mom"), the option with "to" sounds at least a bit clumsy and I would definitely recommend the option with "jest". But we do try to accept 'to' as well, it's technically okay.

'to' is a bit like saying X = Y, and 'jest' is more of a descriptive thing. But in most sentences both should be fine.

June 28, 2017

Got it, thank you! I really appreciate the work you do. Many a time I've had a question about a sentence, opened the discussion, and found that you've already answered it. So thank you also for all the times my only thanks have been a lingot or two. :)

June 28, 2017

I keep seeing people say things along the lines of "'to' is a bit like saying X = Y", but that doesn't make sense given that you can say "Psy to zwierzęta" for "dogs are animals". It's not the case that dogs = animals, so what gives?

October 13, 2018

This is great! Thanks for putting all the effort and time in it!

However, I have noticed something I don't get in part 1,5, regarding the question what is X and what is Y.

You wrote: "So I think I'd say that it's the matter of what defines what."

Then you give several examples, of which I will quote two:

  1. "Kot jest zwierzęciem" "A definition of 'a cat', although a very simplified one, is that it is in fact 'an animal'. "

So we see: X=cat (nom.), Y=animal (instr.) and Y is a definition of X. Very clear!

  1. "Znalezienie wyjścia jest twoim zadaniem" "Your task can be defined (precised) by saying that it is "to find the exit". "

So here we see: X = to find an exit (nom.), Y = your task (instr.), but you wrote that X is a definition of Y. That's the other way around!

I struggle to understand whether 'your task' is the definition of 'finding the exit', or 'finding the exit' is the definition of 'your task'. My sense of logic would opt for the latter, but Polish grammar disagrees :-)

August 17, 2017
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Well, that was anyway a very specific and unusual example. For sure you can't say "Twoje zadanie jest znalezieniem wyjścia"... so I'd say that "znalezienie wyjścia" can be defined by being your task. Actually, maybe this is where the most important thing is: "Finding an exit" is "a task". But "The task" cannot be "a finding an exit".

August 17, 2017

Nie wiem czy wyrażę się zrozumiale, ale próbuję zawsze widzieć jaki obydwóch przedmiotów sprawuje funkcę większej grupy.

Zwierzęta: słonie, konie, koty, psy, ptaki, ...
Moje zadania: sprzątać łazienkę, odrabiać lekcje, iść na zakupy, ...

Odwrócone to niemożliwe.

October 20, 2017

Thank you.

You have given me a lot more confidence in using the instrumental case to define one noun-phrase in terms of another.

It has always worried me that English relies so much on hand waving and tone of voice to covey this sense of direction.


"A square IS a RECT-angle," said the maths teacher using two hands to form right angles to frame his own his exasperated face, first portrait then landscape then square!

Q. Does anyone know WHY the instrumental case was chosen for defining. Or was there always a 'defining case' that then became the instrumental?

February 20, 2018
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You're welcome :)

That would need some kind of a language historian to answer, but I think it has always been like that...

I wouldn't get too much into the cases names. As you see here, Instrumental is not only for instruments, just like Locative is not only about location, but also about topics... and some prepositions denoting location do not take Locative actually.

February 21, 2018

Thanks a lot! Lingots for you!

June 9, 2018

So here's my question...

There are certain pairs of sentences you've mentioned where apparently you can use either być or to:

Pies jest zwierzęciem. - Pies to zwierzę.
Psy są zwierzętami. - Psy to zwierzęta.
Pies nie jest zwierzęciem. - Pies to nie zwierzę.
Ten zielony mebel jest drewnianym stołem. - Ten zielony mebel to drewniany stół.
Te zielone meble są drewnianymi stołami. - Te zielone meble to drewniane stoły.
Twoim zadaniem jest znalezienie wyjścia. - Twoje zadanie to znalezienie wyjścia.
Znalezienie wyjścia jest twoim zadaniem. - Znalezienie wyjścia to twoje zadanie.

For these examples, is there any difference at all in meaning or nuance between the two ways of saying it, or are they exactly the same? Is there ever any particular reason to choose one way over the other way, or is the choice completely arbitrary?

October 16, 2018
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A very slight difference exists only in Twoim zadaniem jest znalezienie wyjścia. - Twoje zadanie to znalezienie wyjścia. Znalezienie wyjścia jest twoim zadaniem. - Znalezienie wyjścia to twoje zadanie.

In Polish the last word/noun phrase is the most important and gets the "phrasal accent".

Therefore in the phrases "Twoim zadaniem jest znalezienie wyjścia" and "Twoje zadanie to znalezienie wyjścia" it is stressed that the task is to find the exit (and not to find something else).

In the phrases "Znalezienie wyjścia jest twoim zadaniem" and "Znalezienie wyjścia to twoje zadanie" it is stressed that finding the exit is your task (and not somebody's else).

October 16, 2018

That's good to know, thanks!

My main question, though, is how the left sentence in each pair is different from the right sentence; I'm not trying to ask how one pair differs from another pair.

October 16, 2018
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In the cases above - there is no difference, only a matter of personal choice. The difference is only where I pointed it out.

In some cases however, there may be a difference: e.g. when it comes to set phrases.

  • Nobody says "Czas jest pieniądzem", only "Czas to pieniądz" (Time is money).
  • Another sample: not "Pieniądze nie są wszystkim" but Pieniądze to nie wszystko.

Also, when the subject of the sentence is a noun phrase (i.e. the subject consists of more than 1 word), it is more likely to use the "to" structure instead of the verb "być".

Another case - which is somewhat beyond the topic of the above explanations - is when the object of the sentence is not a noun, but an adverb or a numeral, especially an indefinite numeral. In such cases you have to use the "to" structure. A sample:

  • "Trzydzieści lat to nie jest dużo" (Thirty years is not much)
October 16, 2018


February 16, 2019

two questions: W poniedziałek są urodziny Moniki. (On Monday there's Monika's birthday). Why is it not, On Monday, "it's" Monika's birthday (and not "there's"...or is that is the sense, e.g. there's Monika's birthday (to which to look forward) and: Tu jest Polska, tu się pije! (Here is Poland, one drinks here!) why is is not 'this' is Poland...or does in mean, here is Poland (as in a list,: here is Poland, one ..., here is Germany, one... etc.)?

but all the above is a great help...thanks

February 17, 2019
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Your translations are definitely more natural English, but they are a bit further from Polish in terms of wording. My translations were as close as possible while (hopefully) still being correct, although true, a bit strange.

February 17, 2019
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