Learn Hardcore Russian: Иногда кто‑то из соседей где‑то теряет ключ, и все ищут его по всему подъезду. - Sometimes someone from the neighbors loses a key somewhere, and everyone looks for it throughout the stairwell.

где‑то – “somewhere” with a slightly more specific or real feeling. The speaker imagines there is a definite place, but just doesn’t know which.
- Он где‑то тут живёт. – He lives somewhere around here (I’m pretty sure).
где‑нибудь – “somewhere / anywhere,” more indefinite, uncertain, or careless.
- Давай встретимся где‑нибудь. – Let’s meet somewhere/anywhere.

In this sentence, где‑то теряет ключ suggests that the key is lost in some specific place, just not known to us, which fits a normal, real‑world situation.

Why is the verb теряет used, and not потеряет or теряет vs теряет ключи?

Here теряет is the imperfective present tense of терять (to lose). It’s used for repeated / habitual actions:

Иногда … теряет ключ – Sometimes (someone) loses a key (this happens from time to time).

Потеряет is perfective future – it describes a single, completed loss in the future:

Он потеряет ключ. – He will lose the key (once).

Using теряет here tells us we’re talking about a general pattern of behavior, not one specific incident.

As for ключ vs ключи:

теряет ключ – loses a key (one key at a time; typical / generic).
You could say теряет ключи (loses keys), but it sounds like the person repeatedly loses multiple keys as a set. The singular is more natural for a generic “someone loses their key.”

Why is ключ singular in Russian when in English we might say “lose their keys”?

Russian often uses the singular where English uses a generic plural.

English: “Sometimes a neighbor loses their keys.”
Russian: Иногда кто‑то из соседей теряет ключ.

In Russian, the idea of “a typical incident involving keys” is comfortably expressed with one key in the singular. It doesn’t mean they literally never lose more than one; it’s just the standard way to phrase this pattern.

How do we know that его refers to ключ, not to the neighbor?

In Russian, the pronoun его can mean “his” or “it” (masculine), depending on context. Here, его refers to ключ because:

ключ is masculine in Russian.
The last masculine singular noun that makes sense syntactically is ключ.
The meaning of the sentence strongly supports “they all look for it (the key).”

So все ищут его = everyone looks for it (i.e., the key), not everyone looks for him.

What does по всему подъезду literally mean, and what does по do here?

По всему подъезду literally means “around/throughout the whole stairwell/entrance.”

по
- dative often means “around, over, throughout” a space.
всему – dative singular of весь (all, whole).
подъезду – dative singular of подъезд.

So:

искать по всему подъезду = to search all over the stairwell / up and down the entrance / in every part of the entrance area.

This по + dative is very common:

ходить по городу – to walk around the city
искать по карманам – to search through one’s pockets

What exactly does подъезд mean? It doesn’t sound like just “entrance.”

Подъезд is a culturally specific word:

In a typical multi‑story apartment building in Russia, the building is divided into sections, each with its own door from the street and its own staircase (and now usually an elevator).
Each such section is called a подъезд.

So по всему подъезду means people are searching all through that section of the building: the stairs, the landings on each floor, near the doors, etc. It is more specific than just “entrance” or “staircase,” but those are common dictionary translations.

Why is the present tense used here to describe something that happens “sometimes”?

Russian uses the present tense with adverbs of frequency (like иногда – sometimes) to talk about habitual / repeated actions:

Иногда кто‑то … теряет ключ. – Sometimes someone loses a key.
Я часто опаздываю. – I’m often late.

This is very similar to English:

Sometimes a neighbor loses a key, and everyone looks for it…

Even though it describes events that happen at different times, the simple present (in both languages) is the standard tense for such general, recurring situations.

Can the word order of иногда and где‑то be changed?

Yes, Russian word order is flexible, and you will hear variants like:

Кто‑то из соседей иногда где‑то теряет ключ…
Иногда кто‑то из соседей теряет ключ где‑то… (less usual, but possible)

However, the original:

Иногда кто‑то из соседей где‑то теряет ключ…

sounds very natural because:

Иногда at the beginning sets the time/frequency frame.
где‑то stands close to теряет, tying “somewhere” directly to the action “loses (it).”

Moving them changes the rhythm or emphasis, but not the basic meaning.

Why is there a comma before и in …, и все ищут его по всему подъезду?

There are two independent clauses joined by и:

Иногда кто‑то из соседей где‑то теряет ключ,
и все ищут его по всему подъезду.

Each clause has its own subject and verb:

кто‑то … теряет
все ищут

In such cases (two full sentences joined with и), Russian normally uses a comma before и, especially in written, careful style.

So the comma marks the boundary between two separate but connected actions.

Could the sentence say теряет свой ключ instead of теряет ключ? What’s the difference?

Yes, you can say:

Иногда кто‑то из соседей где‑то теряет свой ключ…

свой explicitly means “one’s own” (his/her/their own). Differences:

теряет ключ – neutral, and in such a typical situation it is usually understood to be their own key anyway.
теряет свой ключ – slightly more explicit or emphatic that it is their own key, not someone else’s.

In this context, свой is optional; the original sentence is completely natural without it.

Why is there no explicit subject like они before ищут?

Russian often omits subject pronouns when the subject is clear from context or is expressed by another word.

Here, все (everyone) is the subject:

и все ищут его… – and everyone looks for it…

Using они as well would sound redundant or incorrect:

✗ и все они ищут его… – possible but marked, adds extra emphasis like “and they all, every one of them, look for it.”

For a neutral statement, все ищут is the natural form.