Wir bestuhlen den Saal oder lassen ihn leer.

Bestuhlen means to provide with chairs / to seat with chairs / to set up chairs in a room or venue.

It comes from der Stuhl (chair) plus the prefix be-, which often makes a verb meaning to provide something with X or to cover/use something with X.

So:

• den Saal bestuhlen = to put chairs in the hall
• einen Raum bestuhlen = to arrange seating in a room

It’s a fairly specific, practical word, often used for events, venues, conference rooms, halls, etc.

Also, it is not related to stehlen (to steal), even though it may look similar at first glance.

Because den Saal is the direct object of the verb bestuhlen.

The noun is:

• der Saal = nominative singular
• den Saal = accusative singular

Since bestuhlen is something you do to the hall, the hall is the object:

• Wir bestuhlen den Saal.

This is a standard accusative object.

A quick comparison:

• Der Saal ist groß. = The hall is big.
  Here der Saal is the subject.
• Wir bestuhlen den Saal. = We are putting chairs in the hall.
  Here den Saal is the object.

Ihn refers back to den Saal.

Since Saal is a masculine noun (der Saal), the accusative pronoun is ihn:

• der Saal → ihn

So:

• lassen ihn leer = leave it empty

You could repeat the noun:

• Wir bestuhlen den Saal oder lassen den Saal leer.

But that sounds repetitive. German, like English, usually uses a pronoun instead:

• Wir bestuhlen den Saal oder lassen ihn leer.

Because the subject is the same in both parts of the sentence, and German can omit it in the second coordinated clause.

Full version:

• Wir bestuhlen den Saal oder wir lassen ihn leer.

More natural and less repetitive:

• Wir bestuhlen den Saal oder lassen ihn leer.

This works because both actions have the same subject: wir.

English does the same thing:

• We’ll set up chairs in the hall or leave it empty.

You can include the second wir, but omitting it is often smoother.

In the second clause, the subject wir is omitted, so the finite verb lassen comes first in that clause.

The full version is:

• ... oder wir lassen ihn leer.

If you leave out wir, you get:

• ... oder lassen ihn leer.

So the word order is not unusual once you mentally restore the subject.

Structure:

• oder wir lassen ihn leer
• shortened to
• oder lassen ihn leer

This is common in coordinated clauses where the subject is understood from the first clause.

Here lassen means leave.

So:

• etwas leer lassen = to leave something empty

That is different from the let/have uses of lassen, such as:

• Ich lasse ihn gehen. = I let him go.
• Ich lasse mein Auto reparieren. = I have my car repaired.

In your sentence, the meaning is simply:

• lassen ihn leer = leave it empty

So leer describes the state the hall remains in.

Because leer is not being used before a noun here. It is a predicate adjective.

Compare:

• ein leerer Saal = an empty hall
  Here the adjective comes before the noun, so it takes an ending: leerer
• Der Saal ist leer. = The hall is empty.
  Here it is a predicate adjective, so it has no ending
• Wir lassen ihn leer. = We leave it empty.
  Same idea: leer stays unchanged

So in your sentence, leer is describing the object ihn after lassen, not directly modifying a noun in front of it.

No. Bestuhlen is inseparable because of the prefix be-.

So you do not split it:

• Wir bestuhlen den Saal. ✅
• Wir stuhlen den Saal be. ❌

This also affects the past participle:

• bestuhlt = provided with chairs / seated

For example:

• Der Saal ist bereits bestuhlt. = The hall is already set up with chairs.

Notice there is no ge- in the participle, which is typical for verbs with inseparable prefixes like be-, ver-, er-, zer-, etc.

Yes. German often uses the present tense to talk about future plans, especially when the context already makes the time clear.

So:

• Wir bestuhlen den Saal oder lassen ihn leer.

can mean something like:

• We’ll put chairs in the hall or leave it empty.
• We are going to set up chairs in the hall or leave it empty.

German does not need a special future form as often as English does.

If you wanted to make the future more explicit, you could say:

• Wir werden den Saal bestuhlen oder ihn leer lassen.

But in many everyday situations, the plain present tense is more natural.

Yes, but the structure depends on the kind of clause.

In a normal main clause with the subject included:

• Wir lassen ihn leer.

If the subject is omitted after oder, the finite verb comes first in that clause:

• ... oder lassen ihn leer.

So in your sentence, lassen ihn leer is correct because it is a shortened coordinated clause.

You would see ihn leer lassen in places where the infinitive is needed, for example:

• Wir wollen ihn leer lassen. = We want to leave it empty.

So:

• lassen ihn leer = finite verb clause
• ihn leer lassen = infinitive phrase

Yes, very much so.

The conjunction oder means or, so the sentence presents two alternatives:

1. Wir bestuhlen den Saal
   = we set up chairs in the hall
2. (wir) lassen ihn leer
   = we leave it empty

So the overall sense is that the hall will either be arranged with chairs or left without them.

This can sound practical or logistical, for example in event planning.