Подруга поїхала, і я сумую за нею.

Подруга means female friend, while друг means male friend or friend in a masculine form.

Since the sentence is talking about a female friend, подруга is the correct word.

A useful note for English speakers: подруга usually means female friend, not automatically girlfriend in the romantic sense. Context matters.

In the past tense, Ukrainian verbs agree with gender and number.

• поїхав = he went / left
• поїхала = she went / left
• поїхало = it went
• поїхали = they went

Because подруга is feminine, the verb also takes the feminine past form: поїхала.

Поїхала is the past tense of поїхати, which usually means to go away / leave by transport or set off.

It often suggests travel by some vehicle, not just going on foot.

So Подруга поїхала means something like:

• My female friend left
• My female friend went away
• My female friend departed

It gives a sense of completed departure.

This is about aspect, which is very important in Ukrainian.

• їхати is imperfective: it focuses on the process, like was going / used to go / was traveling
• поїхати is perfective: it focuses on the start or completion of leaving, like left / set off

In this sentence, the idea is that the friend has already gone away, so поїхала is natural.

Yes, it can often be omitted.

Ukrainian verbs usually show who is doing the action, so сумую already means I miss / I am sad / I long.

So both are possible:

• і я сумую за нею
• і сумую за нею

Including я adds emphasis or clarity. It can feel a bit more contrastive, like and I miss her.

Сумую is the first person singular present tense of сумувати.

It can mean:

• I am sad
• I feel sorrow
• I miss someone

In this sentence, because it is followed by за нею, it means I miss her.

So сумувати за кимось = to miss someone.

Because the verb сумувати requires a specific pattern:

сумувати за + instrumental case

So:

• сумую за мамою = I miss my mother
• сумую за другом = I miss my male friend
• сумую за нею = I miss her

This is something you mainly have to memorize as a verb pattern. English says miss someone, but Ukrainian uses a preposition: miss for/after someone, roughly speaking.

Because the preposition за here requires the instrumental case.

The pronoun вона changes by case:

• вона = she
• її / її = her
• нею = by/with/her, and also after some prepositions, including за in this pattern

So after сумувати за, you need the instrumental form:

• за нею = after her / miss her

This is why вона and її do not work here.

This is a common feature of Ukrainian pronouns after prepositions.

The pronoun forms with ї- / не- can change after a preposition, and an extra н often appears:

• її → after some prepositions: до неї
• нею is the instrumental form used after a preposition here: за нею

So the н is not random; it is a normal grammatical feature of pronouns after prepositions.

Because the sentence joins two clauses:

• Подруга поїхала
• я сумую за нею

Each clause has its own verb, so Ukrainian normally puts a comma before і when linking two full clauses like this.

So the punctuation is standard.

Not completely. Ukrainian word order is more flexible than English, though the original sentence is the most neutral.

Neutral order:

• Подруга поїхала, і я сумую за нею.

You could also hear:

• Подруга поїхала, і за нею я сумую.
• Я сумую за нею, бо подруга поїхала.

Changing word order usually changes emphasis, not the core meaning.

Usually, by itself, подруга means female friend.

If someone wants to clearly say girlfriend in the romantic sense, Ukrainian often uses other wording depending on context, such as:

• моя дівчина = my girlfriend
• sometimes кохана = beloved

So in most learning contexts, подруга should first be understood as female friend.

Then both the noun and the past-tense verb would change:

• Друг поїхав, і я сумую за ним.

Compare:

• подруга → друг
• поїхала → поїхав
• за нею → за ним

This is a good example of how Ukrainian shows gender in both nouns, verbs in the past tense, and pronouns.