Learn Hardcore Greek: Έχω την ευθύνη να φροντίζω τον σκύλο μας, και είμαι ευγνώμων που η αδερφή μου με βοηθάει. - I have the responsibility to take care of our dog, and I am grateful that my sister helps me.

η ευθύνη = nominative (used for the subject of the sentence)
- e.g. Η ευθύνη είναι μεγάλη. – The responsibility is big.
την ευθύνη = accusative (used for the direct object)

In Έχω την ευθύνη..., the subject is (εγώ) “I”, and την ευθύνη is the thing I have, so it is a direct object and must be in the accusative: την ευθύνη.

Why do we say την ευθύνη να φροντίζω and not something like την ευθύνη του να φροντίζω or για να φροντίζω?

In Greek, a very common pattern is:

noun + να + verb

to express things like the responsibility to do, the ability to do, etc.

την ευθύνη να φροντίζω = the responsibility to take care (of...)
να here introduces a subordinate clause and functions where English would use to or to + verb.

του να φροντίζω or για να φροντίζω would sound unnatural here:

την ευθύνη του να φροντίζω – overly clunky/rare in modern speech
την ευθύνη για να φροντίζω – sounds like the responsibility in order for me to take care, which is not the usual construction.

Why is it να φροντίζω and not να φροντίσω?

Both forms are subjunctive, but they differ in aspect:

να φροντίζω (imperfective) = ongoing, repeated, habitual action
→ suggests regularly taking care of the dog.
να φροντίσω (perfective) = single, complete action
→ would suggest to take care of the dog once / on a specific occasion.

Because ευθύνη here is about an ongoing duty, the continuous form να φροντίζω is the natural choice.

What exactly does να mean in να φροντίζω? Is it like English to?

να doesn’t have a one‑word English equivalent. It:

marks the subjunctive mood;
appears after many verbs and nouns (θέλω, πρέπει, μπορώ, ευθύνη, ευκαιρία, from wishes, etc.);
often corresponds to “to” + verb or “that” + clause in English.

So να φροντίζω is a subjunctive clause that, in this sentence, matches English to take care of in meaning, but να itself is not a pure “to”; it is a grammatical marker of the subjunctive.

Why is it τον σκύλο and not το σκύλο?

The noun σκύλος is masculine:

nominative: ο σκύλος
accusative: τον σκύλο

In standard modern Greek you keep τον even when the following word starts with a consonant:

Βλέπω τον σκύλο. – I see the dog.

In fast or very informal speech, people sometimes say το σκύλο, but τον σκύλο is the correct and neutral form.

Why is μας after τον σκύλο (τον σκύλο μας) and not before, like English our dog?

Greek possessive pronouns in this form (μου, σου, του, της, μας, σας, τους) are clitics and normally come after the noun (with the article in front):

το βιβλίο μου – my book
η μητέρα σου – your mother
τον σκύλο μας – our dog

So the structure is:

article + noun + possessive
τον + σκύλο + μας

Putting μας before (μας σκύλο) is not grammatical in modern Greek.

Could we just say Έχω ευθύνη να φροντίζω τον σκύλο μας without την?

You can, but the nuance changes slightly:

Έχω ευθύνη να... – more general: I have (some) responsibility to...
Έχω την ευθύνη να... – more specific/definite: I have *the responsibility to..., i.e. *it’s my particular duty.

In this context, την ευθύνη implies that the speaker is the one specifically in charge of the dog, which fits naturally.

What part of speech is ευγνώμων? Is it a verb?

ευγνώμων is an adjective, not a verb. It means “grateful, thankful”.

The structure is:

είμαι ευγνώμων – I am grateful.

So:

subject: (εγώ) – I
verb: είμαι – am
complement (adjective): ευγνώμων – grateful

It works like English I am happy / I am tired / I am grateful.

Does ευγνώμων change for gender and number?

Yes. ευγνώμων behaves like an adjective. Common forms:

masculine singular: ευγνώμων
feminine singular: ευγνώμων (same spelling; context/or article shows gender)
neuter singular: ευγνώμον
plural (all genders): ευγνώμονες

In είμαι ευγνώμων, we usually don’t see gender because εγώ is not stated and the form is the same for masculine and feminine in the nominative singular. Context (speaker’s gender) would decide it.

Why is it που η αδερφή μου με βοηθάει and not ότι η αδερφή μου με βοηθάει?

Both που and ότι can sometimes be translated as that, but they’re used differently.

After adjectives expressing emotion (χαρούμενος, λυπημένος, ευγνώμων, κτλ.), modern Greek strongly prefers που:

Είμαι ευγνώμων που η αδερφή μου με βοηθάει.
Είμαι χαρούμενος που ήρθες.

ότι is more neutral/“factual”, often following verbs of saying/thinking:

Ξέρω ότι έχει σκύλο. – I know that he has a dog.

So ευγνώμων που... is the natural pattern; ευγνώμων ότι... sounds odd or too formal/old-fashioned.

Could we change the word order to που με βοηθάει η αδερφή μου? Is that correct?

Yes, that is grammatically correct:

που η αδερφή μου με βοηθάει
που με βοηθάει η αδερφή μου

Both mean that my sister helps me.

Differences:

που η αδερφή μου με βοηθάει is more neutral.
που με βοηθάει η αδερφή μου slightly emphasizes με βοηθάει (the helping action), and η αδερφή μου comes later as the agent.

In everyday speech, both orders are common; the original one is a bit more straightforward for learners.

Why is it με βοηθάει and not βοηθάει με?

The pronoun με is a clitic object pronoun (“me”), and in standard Greek it normally appears before the verb in simple tenses:

με βοηθάει – she helps me
με βλέπει – he sees me
με αγαπά – she loves me

So the general order is:

clitic pronoun + verb
με + βοηθάει

βοηθάει με would be understood as “helps with [something]” if με were interpreted as the preposition with, but with a pronoun meaning “me” in this sentence, that order is ungrammatical. For the object “me”, you must say με βοηθάει.

What is the difference between βοηθάει and βοηθά?

They are just two valid present-tense forms of the same verb form (3rd person singular):

βοηθάει – more colloquial, very common in speech
βοηθά – a bit shorter, often seen in writing, also used in speech

Both mean he/she/it helps.

So you can say either:

η αδερφή μου με βοηθάει
η αδερφή μου με βοηθά

with no difference in meaning.

Why is it αδερφή and not αδελφή? Are these different words?

They are the same word (sister); the difference is spelling/register:

αδελφή – more traditional/standard spelling (closer to Ancient Greek).
αδερφή – more phonetic spelling that matches modern pronunciation better; very common in everyday writing.

Both are correct in modern Greek. In speech, they are pronounced the same way.

Is the comma before και in ..., και είμαι ευγνώμων... necessary?

It is optional here and mainly reflects a pause in speech.

Without comma: Έχω την ευθύνη να φροντίζω τον σκύλο μας και είμαι ευγνώμων που...
→ simply joins two main clauses with και.
With comma: ..., και είμαι ευγνώμων που...
→ adds a slightly clearer pause/emphasis before the second clause.

Both are acceptable; many native speakers would write it without the comma, but having it is not wrong.