Код доступа и климат-контроль уже проверили.

Russian often leaves out the subject when it is clear, unimportant, or meant in a general they / someone sense.

In Код доступа и климат-контроль уже проверили, the verb проверили is plural past tense, so the implied subject is something like they:

• They have already checked the access code and the climate control.

This is a very common Russian pattern. The focus is on the action and the things checked, not on who did it.

It is plural because of the implied subject, not because there are two things being checked.

Russian past tense agrees with the subject, not the object. Here the subject is omitted, but the verb form shows it is understood as plural:

• проверил = he checked
• проверила = she checked
• проверило = it checked
• проверили = they checked

So проверили means they checked or someone checked in a general plural sense.

They are in the accusative case because they are the direct objects of проверили.

The sentence answers the question checked what?

• код доступа
• климат-контроль

However, both nouns are inanimate masculine singular, and for that type of noun, the accusative form looks exactly like the nominative form. So you do not see any ending change here.

That is why they look unchanged even though they are objects.

Because доступа is in the genitive case and depends on код.

Russian often expresses noun + noun combinations as:

• X of Y

So:

• код доступа = code of access = access code

This is a very common pattern in Russian:

• номер телефона = phone number
• центр города = city center
• план поездки = travel plan

So доступа is not the main noun here. The main noun is код, and доступа tells you what kind of code it is.

Уже means already. In Russian, it is commonly placed before the verb or before the part of the sentence it emphasizes.

So:

• уже проверили = have already checked / already checked

This placement is very natural. Russian word order is flexible, but this version sounds neutral and standard.

You could move уже in some contexts for emphasis, but Код доступа и климат-контроль уже проверили is the normal, straightforward order.

This is about aspect.

• проверили = perfective
• проверяли = imperfective

Here проверили shows a completed action: the checking is done.

So the sentence means something like:

• They already checked it.
• It has already been checked.

If you used проверяли, it would suggest the process, repetition, or background action instead:

• They were checking
• They used to check
• They checked it at some point without stressing completion

With уже, perfective проверили is especially natural because already often points to a completed result.

It can cover several related meanings depending on context.

Проверить can mean:

• check
• verify
• test
• inspect

In this sentence, the exact English choice depends on the situation:

• access code might be verified
• climate control might be tested or checked

Russian often uses проверить more broadly than English check in some contexts, so the best translation can vary.

Because it is a compound borrowed term, and in Russian many such compounds are written with a hyphen.

Климат-контроль is a standard written form meaning climate control.

It behaves as a masculine inanimate noun in this sentence. As a direct object in the accusative singular, it looks the same as its dictionary form.

No. In Russian, word order is much freer than in English, so the first noun phrase is not automatically the subject.

Here, код доступа и климат-контроль is the object phrase, even though it comes first. The sentence is structured more like:

• The access code and the climate control, they already checked.

That sounds unusual in English, but in Russian it is perfectly normal.

The verb form проверили tells you there is an implied plural subject, not that the first nouns are the subject.

Yes, very often.

Even though the Russian sentence is grammatically active, English may prefer a passive translation if the doer is unknown or unimportant.

So besides They already checked the access code and the climate control, English could also say:

• The access code and the climate control have already been checked.

That is often the most natural English rendering when Russian uses this kind of subjectless plural verb.

Usually not very much, but the emphasis could change.

For example:

• Уже проверили код доступа и климат-контроль.
• Климат-контроль и код доступа уже проверили.

These are all possible, but they sound slightly different in focus.

The original sentence is neutral and natural. It starts with the things that were checked, then gives the information that this has already been done.

Russian uses word order more for emphasis and information structure than English does.