Abonatul păstrează cartela SIM.

Romanian usually puts the definite article at the end of the noun, instead of using a separate word before it.

So:

• abonatul = the subscriber
• cartela = the card

This is one of the biggest differences from English. In Romanian, the is often attached to the noun itself.

Because the nouns have different genders and Romanian uses different definite article endings.

• abonat is masculine

  • abonat = subscriber
  • abonatul = the subscriber

• cartelă is feminine

  • cartelă = card
  • cartela = the card

So the different endings reflect normal Romanian article patterns:

• many masculine singular nouns take -ul
• many feminine singular nouns take -a

The basic noun is cartelă. When it becomes definite, the ending changes to cartela.

So:

• cartelă = a card
• cartela = the card

For many feminine nouns ending in -ă, the definite singular form ends in -a. This is normal and not unique to this word.

In this sentence, cartela SIM is the direct object, but its form is the same as the nominative/accusative definite singular.

păstrează is:

• present tense
• 3rd person singular
• from the verb a păstra = to keep / to retain

So this form can go with:

• el păstrează = he keeps
• ea păstrează = she keeps
• abonatul păstrează = the subscriber keeps

Romanian verbs often show the person clearly, so the form itself gives useful grammatical information.

Because Romanian often omits subject pronouns when the subject is already clear.

Here, the subject is explicitly named:

• Abonatul păstrează cartela SIM.

Since abonatul already tells you who is doing the action, there is no need to add el.

Romanian does this much more often than English. In fact, adding the pronoun can sound emphatic or contrastive:

• El păstrează cartela SIM. = He keeps the SIM card.

The sentence uses the most neutral and common order:

• Subject + Verb + Object
• Abonatul păstrează cartela SIM.

That is the normal default order in Romanian, just like in English.

However, Romanian word order is often a bit more flexible than English for emphasis or style. The default version here is the most straightforward and natural one for a basic statement.

The Romanian letter ă is a short central vowel, similar to the a in English sofa or the first sound in about.

So in păstrează, both ă sounds are this special Romanian vowel.

This letter is very common in Romanian, and it is different from plain a.

Usually no. SIM is an acronym, and in this sentence it stays unchanged.

The Romanian grammar is carried by the noun before it:

• cartela SIM = the SIM card

So the definite article is attached to cartela, not to SIM.

cartela SIM is a normal and understandable Romanian expression, especially in telecom or official language.

You may also hear:

• card SIM
• cartelă SIM

In practice, Romanian often accepts more than one version for modern technical vocabulary. The sentence you were given is perfectly standard.