Learn German: Wir üben, bevor das Stück anfängt. - We practice before the play begins.

The word bevor (before) is a subordinating conjunction. This means it introduces a dependent clause and forces the conjugated verb (anfängt) to move to the very end of that clause.

anfangen (to begin) is a separable verb. Why isn't it split into fängt ... an in this sentence?

Normally, it does separate (like in Das Stück fängt an). However, when a word like bevor pushes a separable verb to the end of the sentence, the prefix and the verb are forced back together into a single word (anfängt).

I learned that das Stück means 'the piece'. Why is it translated as 'the play' here?

While das Stück literally means 'the piece' (like a piece of cake), it is frequently used in arts and entertainment as a shortened version of das Theaterstück (the theatrical play) or a musical piece.

Do I always need a comma before bevor?

Yes! Unlike in English, German punctuation rules strictly require a comma to separate the main clause (Wir üben) from a subordinate clause (the part starting with bevor).