Learn Hardcore Romanian: Când soarele apune, stelele apar și tramvaiul este gol. - When the sun sets, the stars appear and the tram is empty.

Când is a subordinating conjunction meaning “when.” It introduces a temporal clause (“when the sun sets”) and is followed by a comma because the subordinate clause comes before the main clause.

Why do soarele, stelele and tramvaiul end in -le?

In Romanian, the definite article is attached as a suffix.

soare (sun) → soarele (“the sun”)
stele (stars) → stelele (“the stars”)
tramvai (tram) → tramvaiul (“the tram”)
The endings differ by gender and number:
Masculine singular often ends in -l or -ul
Feminine plural ends in -le

How is apune conjugated and does it need a reflexive pronoun?

Apune is the 3rd person singular present of the intransitive verb a apune (“to set” as in the sun).
Conjugation in present tense:
eu apun
tu apui
el/ea apune
noi apunem
voi apuneți
ei/ele apun
There is no reflexive pronoun here; a apune is not reflexive.

Why is the verb apar used with stelele?

Apari is the root of a apărea (“to appear” or “to show up”). In present tense, 3rd person plural is apar to agree with stelele (plural). So stelele apar means “the stars appear.”

Could I invert the clauses and say Stelele apar când soarele apune?

Yes, you can invert them:
“Stelele apar când soarele apune.”
Note that when the subordinate clause comes second, the comma is optional, especially in spoken Romanian. The meaning stays the same.

Why is și used to join stelele apar and tramvaiul este gol rather than a semicolon or another conjunction?

Și simply means “and,” linking two coordinate main clauses. Alternatives:

Use a semicolon: “Stelele apar; tramvaiul este gol.”
Use apoi (“then”): “Stelele apar, apoi tramvaiul este gol.”
Each choice slightly changes the style or emphasis.

Can we drop the definite article and say soare apune, stele apar și tramvai gol?

Dropping the article makes the nouns indefinite or generic. You’d lose specificity:

“Soare apune” reads like an abstract or poetic phrase, not “the sun sets.”
“Tramvai gol” is “an empty tram,” not “the tram is empty.”
In daily Romanian, you normally need the article here.

Why is there a comma after apune but not before și?

The comma after apune separates the initial subordinate clause from the main clause. There’s no comma before și because it simply joins two balanced main clauses without introducing a new subordinate idea.