Ei merg la parc dimineața și seara.

Ei means they and refers to a masculine group or a mixed group of males and females.

It is not always necessary in Romanian, because Romanian often drops subject pronouns when the verb already makes the subject clear. So:

• Ei merg la parc dimineața și seara.
• Merg la parc dimineața și seara.

Both can be correct, depending on context.

However, ei can be useful:

• for emphasis
• for contrast
• because merg can also mean I go, so the pronoun helps make they explicit

Merg is the present tense of a merge (to go).

Here is the present tense:

• eu merg = I go
• tu mergi = you go
• el/ea merge = he/she goes
• noi mergem = we go
• voi mergeți = you all go
• ei/ele merg = they go

A detail that often surprises learners: eu merg and ei/ele merg have the same form. That is one reason why using ei can help.

In Romanian, after la with a destination like park, school, store, etc., it is very common to use the noun without the definite article:

• la parc = to the park
• la școală = to school
• la magazin = to the store/shop

English often uses the, but Romanian does not always match that pattern.

You would use parcul if you were referring to a specific, clearly identified park, especially if it is further specified:

• la parcul din centru = to the park downtown
• la parcul acela = to that park

So la parc is a normal, natural way to say to the park in a general sense.

La is a very common preposition. Its meaning depends on context, but here, with a merge, it means to:

• merg la parc = I/they go to the park

In other contexts, la can also mean things like at or to someone's place, for example:

• Sunt la parc. = I am at the park.
• Merg la Maria. = I’m going to Maria’s place.

So the verb helps determine the best English translation.

Romanian often expresses times of day without a separate preposition like English in.

So:

• dimineața = in the morning
• seara = in the evening
• noaptea = at night
• după-amiaza = in the afternoon

English needs a preposition here, but Romanian usually does not. This is just a normal structural difference between the two languages.

These are very common Romanian adverbial time expressions. Historically and grammatically, they are related to the nouns morning and evening, but in this kind of sentence they function as time adverbs:

• dimineața = in the morning
• seara = in the evening

So even though they look like noun forms, you should often learn them as fixed expressions of time.

This is very common in Romanian, and learners usually just memorize them as whole units.

Yes, very often it does.

Romanian present tense can express:

• something happening now
• a repeated action
• a general habit

In this sentence, dimineața și seara strongly suggests a habitual action, so the idea is usually:

• they go to the park in the morning and in the evening
• or more naturally in English, every morning and evening

The exact nuance depends on context, but a repeated routine is the most natural reading.

Yes. Romanian word order is fairly flexible.

The original sentence is perfectly natural:

• Ei merg la parc dimineața și seara.

But other orders are also possible, for example:

• Dimineața și seara, ei merg la parc.
• Ei merg dimineața și seara la parc.

The differences are mainly about focus or style, not basic meaning.

A rough guide:

• putting dimineața și seara first gives more emphasis to when
• keeping la parc closer to merg sounds very neutral and natural

Yes, if the group is entirely female.

• ei = they (masculine or mixed group)
• ele = they (all-female group)

So:

• Ei merg la parc dimineața și seara. = They go to the park in the morning and in the evening.
  (masculine or mixed)
• Ele merg la parc dimineața și seara. = They go to the park in the morning and in the evening.
  (all female)

The verb merg stays the same.

Și means and.

It is pronounced roughly like she in English.

A useful spelling point:

• ș = the sh sound
• i here is pronounced like ee

So:

• și ≈ she

This is one of the most common Romanian words, so it is worth learning early.