Primam puno e-mailova na poslu, ali sam jutros otvorila samo jedan, jer sam očekivala važan odgovor od profesorice.

Because primam is describing a habitual / repeated action: I receive a lot of emails at work.

In Croatian, the present tense is often used just like in English for regular actions:

• Primam puno e-mailova na poslu. = I receive / get a lot of emails at work.

Also, primati is the imperfective verb, which fits ongoing, repeated, or general actions.

Because after quantity words like puno (a lot of), Croatian normally uses the genitive plural.

So:

• e-mail = singular
• e-mailovi = nominative plural
• e-mailova = genitive plural

That is why you get:

• puno e-mailova = a lot of emails

This is a very common pattern:

• puno ljudi = a lot of people
• puno knjiga = a lot of books
• puno vremena = a lot of time

Na poslu means at work.

Literally, it is something like on the job / at work, but the natural English translation is simply at work.

This is a fixed, very common expression:

• na poslu = at work
• biti na poslu = to be at work

So:

• Primam puno e-mailova na poslu = I get a lot of emails at work

Because Croatian past tense here is formed with:

• the auxiliary sam (am / have historically, but just part of the past tense now)
• plus the l-participle: otvorila

So:

• sam otvorila = I opened

Croatian perfect tense works like this:

• sam otvorila = I opened
• si otvorila = you opened
• je otvorila = she opened

In this sentence, past time is needed for opened, so the auxiliary must be there.

The ending shows that the speaker is female.

In Croatian past tense, the participle agrees with the subject’s gender:

• otvorila / očekivala = if the speaker is female
• otvorio / očekivao = if the speaker is male

So this sentence was said by a woman.

If a man said it, it would be:

• ...ali sam jutros otvorio samo jedan, jer sam očekivao...

Because sam is a clitic (an unstressed short word), and Croatian clitics usually appear near the beginning of the clause, in a special position often called second position.

So this is natural:

• ali sam jutros otvorila...

Here the conjunction ali helps introduce the clause, and the clitic sam comes immediately after it.

Croatian word order is flexible, but clitics have special placement rules. English speakers often notice this early because it does not work like normal English word order.

Jutros means this morning.

It is an adverb, so Croatian does not need a preposition here.

Compare:

• jutros = this morning
• danas = today
• jučer = yesterday
• sutra = tomorrow

So:

• sam jutros otvorila samo jedan = I opened only one this morning

Because the noun is omitted when it is already obvious from context.

Earlier in the sentence, we already have e-mailova, so Croatian can simply say:

• samo jedan = only one

The missing noun is understood to be e-mail.

Also, jedan is in the masculine singular form because e-mail is masculine:

• jedan e-mail

This kind of omission is very common and natural in Croatian, just like in English:

• I opened only one.

Yes. Očekivala comes from the imperfective verb očekivati.

That fits the meaning well because expecting is viewed here as an ongoing state/background situation:

• jer sam očekivala važan odgovor...
• because I was expecting an important reply...

Imperfective verbs are often used for:

• ongoing situations
• repeated actions
• background descriptions

That is why očekivala sounds natural here.

Because važan must agree with odgovor.

• odgovor is masculine singular
• so the adjective is also masculine singular: važan

Here odgovor is the object of očekivala, but since it is a masculine inanimate noun, its accusative form looks the same as the nominative:

• važan odgovor

Compare with a feminine noun:

• važnu poruku = an important message

So the form is correct because of normal adjective-noun agreement.

Profesorice is in the genitive singular, because it follows the preposition od (from).

So:

• od profesorice = from the female professor / teacher

Important points:

• profesorica = a female professor / teacher
• after od, Croatian uses the genitive
• profesorica → profesorice

If it were a male professor, it would be:

• od profesora

Because there are two separate past-tense verbs:

1. sam otvorila = I opened
2. sam očekivala = I was expecting / I expected

Each past-tense verb needs its own auxiliary.

So Croatian does not normally use one sam for both here. Each clause has its own past-tense form.

Because Croatian punctuation usually separates clauses clearly.

Here the sentence has three parts:

1. Primam puno e-mailova na poslu
2. ali sam jutros otvorila samo jedan
3. jer sam očekivala važan odgovor od profesorice

So the commas mark clause boundaries:

• before ali = but
• before jer = because

This is very normal Croatian punctuation.

Yes, to some extent. Croatian has more flexible word order than English, although not every order sounds equally natural.

For example, these parts can move around for emphasis:

• Jutros sam otvorila samo jedan...
• Samo jedan sam jutros otvorila... (more emphasis on only one)

But the original sentence is natural and neutral:

• Primam puno e-mailova na poslu, ali sam jutros otvorila samo jedan, jer sam očekivala važan odgovor od profesorice.

The main thing to watch is that clitics like sam still need to stay in their normal position.