Learn Hardcore German: Sobald der Stau endet, lasse ich das Fenster herunter und genieße frische Luft. - As soon as the traffic jam ends, I roll down the window and enjoy fresh air.

Sobald translates to “as soon as” and indicates that one action immediately follows another. Wenn can also mean “when” or “whenever,” but is used for repeated events or general conditional statements rather than a single immediate sequence.

Why is there a comma after endet?

Because sobald is a subordinating conjunction introducing a subordinate clause. In German you must separate any subordinate clause from the main clause with a comma.

How is word order affected in the clause introduced by sobald?

In a subordinate clause the finite verb moves to the very end. So after sobald you have subject (der Stau) and then the verb (endet) at the end of that clause.

Why is the verb lasse placed before the subject ich in the main clause?

After the comma the main clause begins. The speaker chose to put the verb in first position to create inversion, so it’s lasse ich instead of ich lasse. German allows either subject-first (V₂) or verb-first (V₁) in main clauses, depending on which element you put in position one.

What is a separable verb, and why does herunter appear at the end?

Herunterlassen is a separable verb: its base is lassen (to let) plus the prefix herunter (down). In main clauses the prefix detaches and travels to the clause’s end, giving lasse … herunter.

Could I use runter instead of herunter, and what’s the difference?

Yes. Runter is the colloquial short form of herunter. Both mean “down,” but herunter is more standard in writing, while runter is typical in speech.

Why is das Fenster in this form—is it nominative or accusative?

It’s accusative because it’s the direct object of lasse. Neuter nouns have the same form (das) in nominative and accusative, so you can’t see the difference in the article alone.

What exactly does lassen mean in das Fenster herunterlassen, and could I use öffnen instead?

Here lassen means “to let down” or “to lower.” While öffnen means “to open,” native speakers usually say Fenster herunterlassen (roll the window down) rather than Fenster öffnen when talking about car windows.

Why is there no article before frische Luft, and why is the adjective frische not frischer?

Luft is an uncountable noun here, so the article is omitted for a general meaning (“fresh air”). Without an article you use strong adjective endings: feminine accusative singular takes -e, hence frische Luft.

Why is there no comma before und genieße frische Luft?

Because und is connecting two verbs (lasse and genieße) in the same main clause with the same subject (ich). German does not require a comma before und in that situation.