Έχοντας κάνει λίγη έρευνα, τελειώσει το ερωτηματολόγιο και μιλήσει με τη συνεργάτιδά μου, ένιωσα ότι η μέρα έκλεισε καλά.

It is an adverbial opening phrase meaning having done a bit of research, finished the questionnaire, and spoken with my colleague.

The idea is that all of these actions happened before the main action ένιωσα.

So the structure is roughly:

• Έχοντας κάνει / τελειώσει / μιλήσει... = having done / finished / spoken...
• ένιωσα... = I felt...

In natural English, this can often sound like after doing... as much as having done....

Because Greek can use one έχοντας and then list several completed actions after it:

• έχοντας κάνει
• τελειώσει
• και μιλήσει

All three depend on the same έχοντας.

This is similar to English:

• Having done some research, finished the questionnaire, and spoken with my colleague...

You do not need to repeat έχοντας before every verb unless you want a heavier or more emphatic style.

Not exactly. The only actual participle here is έχοντας.

The forms κάνει, τελειώσει, and μιλήσει are the invariable verb forms used after έχω / έχοντας in perfect-type constructions:

• έχω κάνει = I have done
• έχοντας κάνει = having done

So in this sentence, they do not change for person, number, or gender.

A useful learner shortcut is:

• έχοντας + this verb form = having + past participle in English

Even though the Greek grammar is built differently.

The subject is understood from the main verb ένιωσα.

So the sentence means:

• I, having done some research, finished the questionnaire, and spoken with my colleague, felt...

In Greek, this kind of opening participial phrase normally has the same subject as the main clause. So the person who did the research is the same person who felt that the day ended well.

Because:

• έρευνα is a feminine singular noun
• λίγη must agree with it in gender, number, and case

So:

• λίγος = masculine
• λίγη = feminine
• λίγο = neuter

Here λίγη means a little / some.

Also, there is no article because λίγη already makes the noun indefinite enough. So λίγη έρευνα is a natural way to say a little research / some research.

Because με takes the accusative case.

So:

• η συνεργάτιδα = the colleague (nominative)
• τη συνεργάτιδα = the colleague (accusative)

After με, Greek uses the accusative:

• με τη συνεργάτιδά μου = with my colleague

Also:

• μου = my
• it usually comes after the noun in this kind of phrase

So literally the structure is:

• with the colleague my

which is normal Greek word order.

Because the final -ν in την is often dropped before certain consonants, and σ in συνεργάτιδα is one of the common places where that happens.

So before σ, both spelling and pronunciation often give you:

• τη συνεργάτιδα

rather than:

• την συνεργάτιδα

In many varieties of Greek, την is also heard more broadly, so you may encounter both. But τη συνεργάτιδά μου is completely normal and standard here.

Because μου is an enclitic word, and Greek spelling adds an extra accent in certain cases.

The base word is:

• συνεργάτιδα

When followed by enclitic μου, it becomes:

• συνεργάτιδά μου

This does not mean the word has changed meaning. It is a spelling rule that helps reflect the stress pattern.

You will see the same thing in many similar phrases.

Because the speaker is presenting both as complete events.

• ένιωσα = I felt at that moment
• έκλεισε = the day ended / wrapped up as a completed whole

The aorist is very common when Greek talks about:

• a finished action
• a single event
• a whole situation seen as complete

So the sentence gives a clear sequence:

1. I did those earlier things
2. then I felt
3. that the day had ended well / wrapped up well

Yes. κλείνω literally means close, but Greek also uses it metaphorically for things like:

• a day
• a period
• a discussion
• a deal
• a chapter of life

So η μέρα έκλεισε καλά means something like:

• the day ended well
• the day wrapped up nicely
• the day closed on a good note

It is idiomatic and natural Greek, not a strange literal translation.

Because ότι introduces a content clause: what exactly the speaker felt.

So:

• ένιωσα ότι... = I felt that...

Here the clause after ότι is:

• η μέρα έκλεισε καλά

Greek often uses ότι or sometimes πως for this kind of that-clause. In this sentence, ότι is perfectly natural.

Yes, the opening έχοντας + verb structure is a bit more written or careful in tone. It is absolutely correct, but in everyday speech many people would more naturally say something like:

• Αφού έκανα λίγη έρευνα, τελείωσα το ερωτηματολόγιο και μίλησα με τη συνεργάτιδά μου, ένιωσα ότι η μέρα έκλεισε καλά.

That version is more straightforward and conversational.

So the original sentence is not unnatural, but it has a slightly more polished, written feel.

Because the sentence begins with a long introductory adverbial phrase:

• Έχοντας κάνει λίγη έρευνα, τελειώσει το ερωτηματολόγιο και μιλήσει με τη συνεργάτιδά μου,

Then the main clause begins:

• ένιωσα ότι η μέρα έκλεισε καλά

The comma helps separate the background actions from the main statement. This is very normal punctuation in Greek.