Emisiile sunt prea mari.

Because -le is the definite article for this plural noun. Romanian often puts the word the at the end of the noun instead of using a separate word in front.

• emisii = emissions
• emisiile = the emissions

So Emisiile sunt prea mari means The emissions are too high/too large.

The singular is:

• o emisie = an emission
• emisia = the emission

The plural is:

• emisii = emissions
• emisiile = the emissions

So the full pattern is:

• singular indefinite: emisie
• singular definite: emisia
• plural indefinite: emisii
• plural definite: emisiile

Because emisiile is plural.

Romanian a fi = to be changes depending on number:

• este / e = is for singular
• sunt = are for plural

So:

• Emisia este prea mare. = The emission is too high.
• Emisiile sunt prea mari. = The emissions are too high.

Because the adjective has to agree with a plural noun.

• mare = singular
• mari = plural

Examples:

• emisia mare = the large/high emission
• emisiile mari = the large/high emissions

In your sentence, emisiile is plural, so the adjective is also plural: mari.

It can mean both, depending on context.

In many contexts involving amounts, levels, or measurements, Romanian uses mare/mari where English often prefers high rather than big.

So in this sentence, prea mari is most naturally understood as:

• too high
• or too large

If the topic is pollution or carbon output, too high is usually the best English translation.

Prea means too, in the sense of more than is acceptable or desirable.

• prea mari = too high / too large

This is different from foarte, which means very.

Compare:

• Emisiile sunt foarte mari. = The emissions are very high.
• Emisiile sunt prea mari. = The emissions are too high.

So prea suggests there is a problem or excess.

Yes. That is the most neutral and natural word order:

• subject + verb + adjective phrase

So:

• Emisiile = subject
• sunt = verb
• prea mari = predicate adjective phrase

Romanian can sometimes change word order for emphasis, but Emisiile sunt prea mari is the standard way to say it.

A useful pronunciation guide is roughly:

e-mi-si-i-le

The two i sounds are both part of the word, so you do hear them separately more than in English. The word has several syllables, not just one final -ii sound swallowed quickly.

A rough English-friendly approximation is:

eh-mee-SEE-ee-leh

The exact pronunciation can vary a little in natural speech, but the important thing is that emisii and emisiile have that extra i because of the plural form.

Yes. The singular noun emisie is feminine.

That matters because Romanian nouns belong to gender classes, and adjectives/articles follow those patterns.

You can see the feminine singular here:

• o emisie
• emisia

And the plural:

• emisii
• emisiile

Even though the adjective form mari is used for plural nouns of more than one gender, the noun itself is still feminine.

Normally, no — that sounds unnatural in standard Romanian.

If you mean the emissions, you need emisiile.

If you want a more general idea like emissions are too high, Romanian often still uses a more specific or more naturally framed structure, depending on context, for example:

• Emisiile sunt prea mari.
• Nivelul emisiilor este prea mare. = The level of emissions is too high.

So for a simple sentence like this, emisiile is the natural choice.

It is in the nominative case because it is the subject of the sentence.

In Romanian, the nominative and accusative often look the same in form, so you usually identify the case by the role in the sentence.

Here:

• Emisiile = subject
• sunt = verb
• prea mari = description of the subject

So this is a straightforward nominative subject.

In a normal full sentence like this, no. Romanian usually keeps the verb to be.

So you should say:

• Emisiile sunt prea mari.

Not:

• Emisiile prea mari. unless you are using it only as a noun phrase, such as the emissions that are too high in a larger sentence.

Romanian is not like Russian or Arabic, where the present-tense to be is often omitted.

You would change both the noun and the adjective to singular:

• Emisia este prea mare. = The emission is too high.

Changes:

• emisiile → emisia
• sunt → este
• mari → mare

This is a good example of how Romanian marks number across the sentence.