Learn Hardcore German: Der Mieter stellt den Kinderwagen nicht im Flur ab, weil die Hausordnung das verbietet. - The male tenant does not park the stroller in the hallway because the house rules forbid it.

Because abstellen is a separable-prefix verb. In main clauses, the finite part (stellt) goes in position 2, and the prefix (ab) moves to the end: stellt … ab. If you use it in a subordinate clause (with a subordinating conjunction like weil), the whole verb goes to the end, e.g., … weil er den Kinderwagen nicht im Flur abstellt.

Why is the verb at the end in the clause with “weil”?

Weil is a subordinating conjunction and forces the finite verb to the end of its clause: … weil die Hausordnung das verbietet. In a main clause, the verb is in position 2: Die Hausordnung verbietet das.

Why is it “den Kinderwagen” instead of “der Kinderwagen”?

Case. Der Mieter is the subject (nominative). Den Kinderwagen is the direct object (accusative masculine singular), so the article changes from der (nom.) to den (acc.). The noun stays the same.

Why is it “im Flur” and not “in den Flur”?

Because it expresses location, not motion. In takes:

Dative for location: im Flur (= in + dem Flur).
Accusative for motion into: in den Flur (into the hallway).

Could the word order with “nicht” be different? What’s the nuance?

Yes. Both are possible:

Der Mieter stellt den Kinderwagen nicht im Flur ab. Focus: not in the hallway (he might put it somewhere else).
Der Mieter stellt den Kinderwagen im Flur nicht ab. Similar meaning; prosody can emphasize “im Flur.” General rule: place nicht before what you negate (here, the location phrase).

Why “nicht” and not “kein”?

Use kein to negate a noun phrase with an indefinite article or no article: Der Mieter stellt keinen Kinderwagen ab (he doesn’t put any stroller). Use nicht to negate the verb or specific adverbials: … nicht im Flur ab.

What does the “das” in “weil die Hausordnung das verbietet” refer to?

It’s a demonstrative pronoun referring to the whole action “putting the stroller in the hallway.” You can also use es here: … weil die Hausordnung es verbietet. Das sounds a bit more specific/emphatic (“that”).

Can I drop “das” and just say “weil die Hausordnung verbietet”?

Not like that. Verbieten is transitive and needs an object. Options:

Keep the pronoun: … weil die Hausordnung das/es verbietet.
Use a zu-infinitive as the object: … weil die Hausordnung verbietet, den Kinderwagen im Flur abzustellen.

Could I say “weil die Hausordnung das nicht erlaubt” instead?

Yes. … nicht erlaubt (does not allow) is the logical opposite of verbietet (forbids) and sounds perfectly natural: … weil die Hausordnung das nicht erlaubt.

Can I use “denn,” “da,” or “deshalb” instead of “weil”?

denn (coordinating): keeps main-clause order. …, denn die Hausordnung verbietet das.
da (subordinating): verb to the end; often used when the reason is assumed to be known. Da die Hausordnung das verbietet, …
deshalb/darum/daher (adverbs): reason in a separate main clause. Die Hausordnung verbietet das; deshalb stellt der Mieter … nicht …

What exactly does “abstellen” mean here?

Here it means “to set down/leave/park temporarily” (e.g., a stroller, bike). Note: abstellen can also mean “to switch off/turn off” (e.g., das Wasser/den Strom abstellen). Context disambiguates.

Why the comma before “weil”?

German requires a comma before subordinate clauses: …, weil … If the reason clause comes first, you still need the comma: Weil die Hausordnung das verbietet, stellt …

What is “im” exactly?

Im is the contraction of in dem (in + the, dative). So im Flur = in dem Flur.

How are the genders and plurals here?

der Mieter (masc.); feminine is die Mieterin; plural die Mieter (mixed) / die Mieterinnen (fem.).
der Kinderwagen (masc.); plural is also die Kinderwagen (no change).
der Flur (masc.); plural die Flure.
die Hausordnung (fem.); plural die Hausordnungen.

What is “Kinderwagen” made of? Is the “-er” a plural ending?

It’s a compound: Kinder (children) + Wagen (carriage). The -er here is part of the linking element from the plural of Kind (Kinder) but in the compound it’s just lexicalized. The noun’s gender is masculine (from Wagen). Plural: Kinderwagen (unchanged).

Could we start with the reason?

Yes: Weil die Hausordnung das verbietet, stellt der Mieter den Kinderwagen nicht im Flur ab. Subordinate clause first, comma, then the main clause (finite verb in position 2).

How would this look in the perfect tense?

Main clause: Der Mieter hat den Kinderwagen nicht im Flur abgestellt, weil die Hausordnung das verbietet.
Note: The participle is one word: abgestellt. In the subordinate clause with weil, you could also use past if needed: …, weil die Hausordnung das verboten hat.

Where would a pronoun object go?

Pronouns tend to stand earlier. Replace den Kinderwagen with ihn:

Der Mieter stellt ihn nicht im Flur ab.
With the reason first: Weil die Hausordnung das verbietet, stellt er ihn nicht im Flur ab.

Is there a difference between “Flur,” “Gang,” “Korridor,” and “Treppenhaus”?

Flur: hallway/corridor inside an apartment or on a floor.
Gang/Korridor: corridor (regional/register differences; Korridor can sound a bit formal).
Treppenhaus: stairwell area. House rules often mention both Flur and Treppenhaus.

Could I express the reason with “wegen”?

Yes, as a prepositional phrase (genitive): Wegen der Hausordnung stellt der Mieter den Kinderwagen nicht im Flur ab. In everyday speech, some use dative after wegen (regional): wegen der Hausordnung is still the same form because fem. genitive = dative here.