Learn Hardcore Greek: Ποια είναι η γνώμη σας για το νέο διαμέρισμα; - What is your opinion about the new apartment?

Ποια (fem.), Ποιος (masc.), Ποιο (neut.) literally mean which and agree in gender with a noun.
Τι is an invariable what, not agreeing with a noun.

In this sentence, Ποια agrees with η γνώμη (feminine), so the literal structure is:

Ποια (which) είναι η γνώμη σας (is your opinion)…

You could say Τι γνώμη έχετε για το νέο διαμέρισμα; (What opinion do you have about the new apartment?), but in the exact structure given, Ποια is the natural choice because it matches the feminine noun γνώμη.

Why is Ποια feminine? How do I know its gender?

Ποια is the feminine form of the interrogative pronoun:

Masculine: Ποιος
Feminine: Ποια
Neuter: Ποιο

It has to agree with the gender of the noun it refers to. Here the noun is η γνώμη (η is the feminine article), so γνώμη is feminine. Therefore, the question word must be feminine too: Ποια.

If the noun were masculine or neuter, you would say:

Ποιος είναι ο φίλος σου; (Which/Who is your friend? – masculine)
Ποιο είναι το πρόβλημα; (What/Which is the problem? – neuter)

What does η γνώμη mean exactly, and why do we need the article η?

γνώμη means opinion.

In Greek, abstract nouns like γνώμη, αγάπη (love), υγεία (health), etc., often take the definite article:

η γνώμη = the opinion

Even when English leaves out the article and just says opinion, Greek often keeps it. So:

What is your opinion? → Ποια είναι η γνώμη σας;

Omitting the article (Ποια είναι γνώμη σας;) is ungrammatical in standard Greek. The article is part of the natural noun phrase.

What exactly is σας here? Is it “you” or “your”? Why this form?

σας is the 2nd-person plural pronoun, and in this sentence it functions as a possessive: your.

Greek uses the weak (clitic) object pronouns for possession in many everyday phrases:

η γνώμη σας = your opinion
το σπίτι μου = my house
το αυτοκίνητό του = his car

σας can mean:

you (object: I see you = σας βλέπω),
your (possession: your opinion = η γνώμη σας),
and it is both plural you and formal you (singular).

Here, σας means your, and it is polite (or plural if speaking to several people).

What is the difference between σας and σου in this kind of sentence?

Both can mean your, but:

σας = your (plural) or polite/formal your (to one person).
σου = your (singular, informal).

So:

Ποια είναι η γνώμη σας για το νέο διαμέρισμα;
- to one person politely (e.g. your landlord)
- or to several people (e.g. a couple).
Ποια είναι η γνώμη σου για το νέο διαμέρισμα;
- to one person you know well (friend, family, someone your age).

The rest of the sentence stays the same; only σας/σου changes the level of formality/number.

Can the word order change? For example, can I say Ποια είναι η γνώμη για το νέο διαμέρισμα σας;

Greek word order is somewhat flexible, but not every order is natural.

These are natural:

Ποια είναι η γνώμη σας για το νέο διαμέρισμα; (standard)
Ποια είναι η γνώμη σας για το νέο διαμέρισμα; (you normally keep σας right after the noun)
Τι γνώμη έχετε για το νέο διαμέρισμα; (a different but common phrasing)

These are not natural:

Ποια είναι η γνώμη για το νέο διαμέρισμα σας; – sounds wrong; σας should attach directly to γνώμη: η γνώμη σας.
Ποια είναι σας η γνώμη για το νέο διαμέρισμα; – also unnatural.

So keep σας glued to η γνώμη: η γνώμη σας.

Why do we use για here? Could we say η γνώμη σας το νέο διαμέρισμα; without it?

για means for / about and is required here to express opinion about something:

η γνώμη σας για το νέο διαμέρισμα = your opinion about the new apartment

Without για, the sentence is incomplete or ungrammatical:

η γνώμη σας το νέο διαμέρισμα → incorrect in this meaning.

Common patterns:

γνώμη για κάτι = opinion about something
Τι γνώμη έχεις για αυτό; = What do you think about this?
Ποια είναι η γνώμη σου για την Ελλάδα; = What’s your opinion about Greece?

You could replace για with longer expressions like σχετικά με (regarding), but you cannot simply omit any preposition.

Why do we say το νέο διαμέρισμα with το? In English we just say “the new apartment” or sometimes “a new apartment”.

διαμέρισμα (apartment/flat) is a neuter noun. Its definite article in the nominative/accusative singular is το:

το διαμέρισμα = the apartment

In this sentence, το νέο διαμέρισμα is in the accusative (object of για), and the article stays το in both nominative and accusative for neuter singular nouns.

Greek almost always uses an article with a specific, known noun:

το νέο διαμέρισμα = the new apartment (a specific one you both know about)

If you wanted a new apartment (non‑specific), you’d say ένα νέο διαμέρισμα.

How does νέο work here? Why is it before διαμέρισμα, and does the position change the meaning?

νέο is the neuter form of the adjective νέος (new/young), agreeing with the neuter noun διαμέρισμα:

Masculine: νέος
Feminine: νέα
Neuter: νέο

It usually goes before the noun in neutral, everyday speech:

το νέο διαμέρισμα = the new apartment

You can also put some adjectives after the noun (especially for emphasis or style), but for simple descriptions like new apartment, adjective + noun is the standard: νέο διαμέρισμα.

What case is η γνώμη σας in, and why? Does the case of σας change?

η γνώμη σας is in the nominative case because it is the subject of the verb είναι (is):

Ποια είναι η γνώμη σας… = Which is your opinion…

In detail:

η – nominative feminine singular article
γνώμη – nominative feminine singular noun
σας – weak pronoun that doesn’t visibly change; its form is the same in genitive and accusative, and it attaches to the noun as a possessive.

The case marking is carried mainly by the article and noun; σας itself looks the same in different roles.

How do you pronounce the tricky parts like γνώμη and διαμέρισμα?

Approximate pronunciation, using English-friendly hints:

Ποια → /pia/
- π like p, ια like ya in yard, but said together: pya.
γνώμη → /ˈɣno.mi/
- γν is like ghn with a voiced, fricative g (like a softer g in go, but “breathier”).
- ώ is stressed o as in more (without the r).
- η here sounds like ee: GNO-mee, with stress on γνώ.
σας → /sas/
- like sas, rhyming with bus but with a as in father.
διαμέρισμα → /ðiaˈme.rizma/
- δ is like English th in this.
- δια → ðya (like thya).
- Stress on μέ: ðya-ME-rizma.

So the whole sentence:

Ποια είναι η γνώμη σας για το νέο διαμέρισμα;
→ /ˈpia ˈine i ˈɣnomi sas ʝa to ˈneo ðiaˈmerizma/

Is this sentence formal or informal? How would I say it informally to a friend?

The sentence as written is formal or polite, because of σας:

Ποια είναι η γνώμη σας για το νέο διαμέρισμα;

To make it informal (to a friend, sibling, etc.) change σας to σου:

Ποια είναι η γνώμη σου για το νέο διαμέρισμα;

You can also choose a more conversational phrasing:

Τι γνώμη έχεις για το νέο διαμέρισμα;
Πώς σου φαίνεται το νέο διαμέρισμα; (How does the new apartment seem to you? / How do you find the new apartment?)

Are there other common ways to ask the same thing in Greek?

Yes, several natural alternatives:

Τι γνώμη έχετε για το νέο διαμέρισμα;
(What opinion do you have about the new apartment?)
Τι νομίζετε για το νέο διαμέρισμα;
(What do you think about the new apartment?)
Πώς σας φαίνεται το νέο διαμέρισμα;
(How does the new apartment seem to you? / How do you find it?)
Informal versions with σου instead of σας.

All are idiomatic; the original Ποια είναι η γνώμη σας για το νέο διαμέρισμα; sounds slightly more formal or careful, often used in surveys, interviews, or polite conversation.

Can I reuse this pattern for other topics? How would I adapt it?

Yes, you can treat it as a template:

Ποια είναι η γνώμη σας για το/την/τον … ;

Just change the object and match the article:

Ποια είναι η γνώμη σας για την ταινία;
(the movie – feminine)
Ποια είναι η γνώμη σας για τον δάσκαλο;
(the teacher – masculine)
Ποια είναι η γνώμη σου για την Ελλάδα;
(Greece – informal σου, feminine noun)
Ποια είναι η γνώμη σας για αυτό το θέμα;
(this topic)

This structure is very common and useful whenever you want to ask someone’s opinion politely.