אבק בנייה נכנס לחדר אחרי ההריסה.

This is a very common Hebrew structure called סמיכות (the construct state).

• אבק בנייה literally means dust of construction
• In natural English, that becomes construction dust

In this structure:

• the first noun is the thing being described: אבק = dust
• the second noun tells you what kind: בנייה = construction/building work

So אבק בנייה means construction dust or dust from construction work.

A useful detail:

• אבק בנייה = construction dust / dust from construction work
• אבק הבנייה = the construction dust / the dust of the construction

The first noun usually does not take ה־ in this structure.

בנייה means construction, building, or building work.

It comes from the root ב־נ־ה, related to building.

In this sentence, אבק בנייה is a standard expression for dust created by:

• construction
• renovation
• drilling
• breaking walls
• similar work

So even though the sentence also mentions demolition (ההריסה), Hebrew still naturally uses אבק בנייה for the kind of dust left by construction/renovation-type work.

Because the subject אבק is a singular masculine noun.

So:

• אבק = dust → grammatically singular masculine
• therefore the verb is נכנס = entered / came in in masculine singular

Even though dust may feel like a mass noun in English, Hebrew still treats אבק as singular here.

If the subject were plural, the verb would also change. For example:

• חלקיקים נכנסו לחדר = particles entered the room

נכנס is the past tense, 3rd person masculine singular form of the verb.

So it means:

• entered
• came in
• went into

Depending on context, any of those can work in English.

Its root is usually analyzed as כ־נ־ס. In modern Hebrew, להיכנס means to enter / to go in / to come in.

So:

• הוא נכנס = he entered / he came in
• אבק בנייה נכנס = construction dust entered / came into

Hebrew often uses ל־ to mean to or into, especially with movement.

So:

• לחדר = to the room / into the room

That is very natural Hebrew.

You can also sometimes use אל, but ל־ is extremely common and often more everyday.

One important spelling point: in unpointed Hebrew, לחדר can represent either:

• לְחֶדֶר = to a room
• לַחֶדֶר = to the room

The writing looks the same without vowel marks. Context tells you which one is meant. In this sentence, it is usually understood as into the room or into the room/the room depending on the translation you were shown.

Because when ל־ combines with ה־, the ה is usually absorbed.

So:

• ל + החדר → לחדר

With vowel marks, the difference is clearer:

• לְחֶדֶר = to a room
• לַחֶדֶר = to the room

Without vowel marks, both are written לחדר.

This is completely normal in Hebrew and also happens with other prepositions like ב־ and כ־.

אחרי means after.

So:

• אחרי ההריסה = after the demolition

This is a very straightforward preposition + noun phrase structure.

You can think of it as:

• אחרי = after
• ההריסה = the demolition

There is also a more formal alternative, לאחר, which also means after. But אחרי is very common in everyday Hebrew.

Because it refers to a specific demolition.

• הריסה = demolition
• ההריסה = the demolition

In this sentence, we are talking about a particular event: the demolition that just happened or has already been mentioned.

So אחרי ההריסה means after the demolition, not just after demolition in general.

The sentence uses a very normal Hebrew word order:

• אבק בנייה = subject
• נכנס = verb
• לחדר = destination
• אחרי ההריסה = time relation

So the structure is basically:

[subject] + [verb] + [place] + [time/context]

Hebrew word order is somewhat flexible, but this version sounds natural and clear.

You could also hear different orders in other contexts, for example to emphasize one part more strongly, but the given sentence is very standard.

A simple pronunciation guide is:

avak bniya nikhnas lakheder akharei haharisa

A slightly more careful version:

• אבק = a-VAK
• בנייה = bni-YA
• נכנס = nikh-NAS
• לחדר = la-KHE-der or la-CHE-der depending on how you represent ח
• אחרי = akha-REI
• ההריסה = haha-ri-SA

A few sound notes:

• ח is a throaty sound not found in standard English
• כ in נכנס here also has that same rough sound
• stress is often near the end of the word in this sentence

Yes. All three are possible depending on the English style of the translation.

• entered sounds a bit more formal
• came in sounds natural and conversational
• went in is possible, though a little less natural for dust in this context

So if the meaning shown to the learner was something like Construction dust came into the room after the demolition, that matches the Hebrew well.

Hebrew נכנס is flexible enough to cover these English choices.