Breakdown of Die Gruppe tanzte synchron, nur dass die Musik zu leise war.
sein
to be
die Musik
the music
zu
too (e.g., too big)
tanzen
to dance
Questions & Answers about Die Gruppe tanzte synchron, nur dass die Musik zu leise war.
How does nur dass affect the word order in the second part of the sentence?
Because nur dass acts as a subordinating conjunction, it creates a dependent clause. This means the conjugated verb—in this case, war—must be pushed to the very end of the clause.
Could I just use aber instead of nur dass here?
You could, but the grammar would change. aber is a coordinating conjunction, which means it doesn't change the word order (you would say: ..., aber die Musik war zu leise). Using nur dass (except that / only that) specifically highlights a single restrictive flaw in an otherwise positive statement, and it forces the verb to the end.
Why doesn't synchron have an ending here, like synchrone?
In this sentence, synchron is acting as an adverb because it describes the verb tanzte (it tells us how they danced). In German, adverbs don't take grammatical endings, so the word stays in its base form.
Why does the sentence use tanzte instead of hat getanzt?
tanzte is the simple past (Präteritum). While you would most likely hear hat getanzt in everyday spoken German, the simple past is standard for written narratives, stories, or formal reports. This sentence reads like a line from a book or a written review.