Der Nachbar ließ die Tür absichtlich offen.

The neighbor deliberately left the door open.

Breakdown of Der Nachbar ließ die Tür absichtlich offen.

• die Tür: the door
• der Nachbar: the neighbor
• offen: open
• absichtlich: deliberately
• lassen: to leave

Questions & Answers about Der Nachbar ließ die Tür absichtlich offen.

What does ließ mean here—is it “let” or “left”?

Here ließ is the simple past of lassen meaning “to leave (something in a certain state)”, not “to allow/let.” So the sentence means “The neighbor deliberately left the door open.”
Example: Er ließ das Licht an. = “He left the light on.”

Why is it ließ (simple past) instead of the present perfect?

Written German often prefers the simple past (Präteritum). In everyday speech, the present perfect (Perfekt) is more common:

• Der Nachbar hat die Tür absichtlich offen gelassen.

Note the placement: the participle is gelassen, and the state word stays with it: offen gelassen.

How does the structure die Tür … offen work?

It’s “object + predicative adjective.”

• die Tür is the direct object.
• offen describes the resulting state of that object.
  Predicative adjectives in German are not declined:
• Er ließ die Tür offen. (predicative, uninflected)
• Compare: die offene Tür (attributive, inflected).

Why is it die Tür (accusative) and not something else?

Because lassen takes a direct object in this pattern. The feminine noun Tür has the same form in nominative and accusative singular (die Tür), so it looks unchanged, but it’s functioning as the accusative object.

Why is absichtlich placed before offen? Can it go elsewhere?

Default and most natural: ließ die Tür absichtlich offen (adverb before the state). Other options for emphasis/flow:

• Der Nachbar ließ absichtlich die Tür offen. (emphasis on intention)
• Absichtlich ließ der Nachbar die Tür offen. (fronted for strong emphasis) Avoid: … offen absichtlich (sounds awkward).

What’s the difference between offen and geöffnet here?

Both can mean “open,” but:

• offen is the normal adjective for a door/window being open.
• geöffnet (past participle of öffnen) is used, but sounds more formal or result-focused, and is common for stores: Das Geschäft ist geöffnet.
  In your sentence, offen is the idiomatic choice. … die Tür geöffnet is possible but less natural.

Can I say ließ die Tür auf instead of offen?

Yes. auf is a common adverb meaning “open” with doors/windows.

• Er ließ die Tür auf. (very idiomatic)
• Opposite: Er ließ die Tür zu. (“He left the door closed.”)
  Both offen lassen and auf lassen are widely used; offen is a bit more neutral/standard.

Could I use verlassen instead of lassen?

No. verlassen means “to leave (depart from) someone/something”:

• Er verließ das Haus. = “He left the house.”
  To leave something in a certain state, use lassen:
• Er ließ die Tür offen.

Why is it Der Nachbar (without -n), but I’ve seen forms like den Nachbarn?

Nachbar is a weak (n-declension) masculine noun in the singular:

• Nominative: der Nachbar
• Genitive: des Nachbarn
• Dative: dem Nachbarn
• Accusative: den Nachbarn
  Here it’s the subject (nominative), so Der Nachbar is correct.

How do you pronounce and spell ließ? What about in Switzerland?

• Pronunciation: [liːs] (like “lees”). The ß is an unvoiced “s.”
• In Germany/Austria, ließ is standard (ß after a long vowel).
• In Swiss spelling, you’ll see liess (no ß).

If I replace die Tür with a pronoun, where does it go?

Pronoun objects tend to come earlier:

• Der Nachbar ließ sie absichtlich offen.
  Without the adverb:
• Der Nachbar ließ sie offen.

How do I say this in the imperative?

• Informal singular: Lass die Tür offen!
• Informal plural: Lasst die Tür offen!
• Formal: Lassen Sie die Tür offen!

Is mit Absicht the same as absichtlich?

Yes, both mean “on purpose.” mit Absicht can sound a bit more emphatic or colloquial:

• Er ließ die Tür absichtlich offen.
• Er ließ die Tür mit Absicht offen.

What’s the opposite of absichtlich?

• aus Versehen or versehentlich = “by accident/accidentally.”
  Example: Der Nachbar ließ die Tür aus Versehen offen. / … ließ die Tür versehentlich offen.

Can ließ be understood as “had [someone] leave it open”?

With lassen + infinitive, lassen is clearly causative: Er ließ die Tür öffnen (“He had the door opened”).
With lassen + object + adjective (as here), it’s normally read as “left [object] [state]” (he himself left it). A causative reading is unusual in this pattern and would typically be expressed with an infinitive: Er ließ die Tür offen stehen / Er ließ die Tür öffnen und offen stehen.