Межевой знак поставили вчера.

Because знак is not the grammatical subject here.

In this sentence, поставили is a common Russian way to say that someone did something, without naming who. Literally, it is they put/placed, but in English we often translate that more naturally as:

• They put up the boundary marker yesterday
• The boundary marker was put up yesterday

This is called an indefinite-personal construction: Russian uses 3rd person plural to mean people / someone / they in a vague, unspecified way.

So:

• поставили = they placed / someone placed
• not the marker placed

Because the sign did not do the action.

If you said знак поставил, that would mean the sign placed something, which does not make sense.

In Межевой знак поставили вчера, the marker is the object of the action, even though it appears in the nominative form. That may feel strange at first to an English speaker, because English would often use a passive sentence here.

Russian often prefers:

• Межевой знак поставили вчера = They put up the boundary marker yesterday

instead of a passive like:

• Межевой знак был поставлен вчера = The boundary marker was placed yesterday

Both are possible, but the active plural version is very common and natural.

Normally yes, direct objects often take the accusative. But here знак is an inanimate masculine noun, and for that type of noun, the accusative singular looks exactly like the nominative singular.

So:

• nominative: знак
• accusative: знак

There is no visible ending change.

That is why the sentence can look confusing at first. Even though знак has the same form as the nominative, its role in the sentence is understood from the verb and the construction.

Compare with a feminine noun, where the form would change more clearly:

• метку поставили вчера = They put down the marker yesterday

Here метку clearly shows accusative.

Межевой means something like boundary-related, demarcation, or land-boundary.

It comes from межа, an older word meaning boundary line between plots of land.

So межевой знак is a fairly specific term meaning a boundary marker, especially in legal, surveying, or land-use contexts.

It is not just any sign or marker; it is one that marks a property boundary or official land division.

Because поставили is perfective, and ставили is imperfective.

Here, the sentence refers to a completed action: the boundary marker was put in place, and that action is finished. Russian usually uses the perfective for that:

• поставили = put / placed / installed as a completed event

If you used ставили, the meaning would shift. It could suggest:

• the process was going on
• repeated action
• background description
• an incomplete or non-result-focused action

So:

• Межевой знак поставили вчера = they put it up yesterday; it was completed
• Межевой знак ставили вчера = they were putting it up yesterday / they put it up yesterday as a process-focused description

For a simple completed event, поставили is the natural choice.

Not formally, no.

Grammatically, it is an active verb form: поставили = they placed.

But in meaning, it often corresponds to an English passive:

• Russian: Межевой знак поставили вчера
• Natural English: The boundary marker was put up yesterday

So the sentence is active in form but often passive-like in translation.

Russian does have a more explicitly passive option:

• Межевой знак был поставлен вчера

That sounds more formal, official, or written. The version with поставили is often more natural in everyday usage.

Yes, Russian word order is flexible.

Вчера at the end is completely natural and neutral here. It puts the time information last:

• Межевой знак поставили вчера

But you can also say:

• Вчера поставили межевой знак
• Межевой знак вчера поставили

These versions are all possible, but the emphasis changes slightly.

Very roughly:

• Межевой знак поставили вчера — neutral; the time comes at the end
• Вчера поставили межевой знак — starts with the time; maybe answering When did they put it up?
• Межевой знак вчера поставили — can sound slightly contrastive, as if clarifying it was yesterday that they put it up

So the end position of вчера is normal and does not mean anything unusual by itself.

Russian has no articles, so межевой знак can mean either:

• a boundary marker
• the boundary marker

The context tells you which one is intended.

For example:

• if you are introducing it for the first time, English might use a
• if both speakers already know which marker is meant, English might use the

Russian leaves that distinction unstated unless some other word makes it clearer.

In this context, поставить often means more than simply put in the everyday sense.

With things like signs, markers, monuments, fences, and similar objects, поставить can mean:

• put up
• set up
• place
• install

So for межевой знак, English translations like these can all work depending on context:

• put up
• placed
• installed

If this is an official land marker, installed or placed may sound especially natural.

The main stresses are:

• межево́й
• знак
• поста́вили
• вчера́

So a helpful pronunciation guide is:

mezheVOY znak posTAveli fchera

A few notes:

• ж in межевой sounds like the s in measure
• вчера begins with a cluster that is often pronounced roughly like fch or vch, depending on speech style
• the stress in вчера́ is on the last syllable

Yes, absolutely.

That version is a true passive:

• Межевой знак был поставлен вчера = The boundary marker was placed yesterday

Compared with Межевой знак поставили вчера:

• поставили version: more conversational, more typical in ordinary speech
• был поставлен version: more formal, more written, more official-sounding

You might see был поставлен in:

• reports
• legal documents
• technical descriptions
• official announcements

In everyday Russian, the active plural version is often preferred even when English would use a passive.