Learn German: Wir müssen das Mikrofon testen, bevor das Publikum kommt. - We have to test the microphone before the audience comes.

The word bevor (before) is a subordinating conjunction. This means it introduces a dependent clause and forces the conjugated verb—in this case, kommt—to the very end of its clause.

Why is testen also at the end of its clause, just before the comma?

The first part of the sentence uses the modal verb müssen (must / have to). When you use a modal verb, it takes the normal second position in the sentence, and the main action verb (testen) gets pushed to the end of that clause in its basic infinitive form.

"Audience" is a group of people. Why is the verb kommt singular instead of plural?

In German, das Publikum is a singular noun, even though it describes a group of many people (a collective noun). Just like you would say "the group comes," you must say das Publikum kommt, not kommen.

Is the comma before bevor always required?

Yes! In German, you must always place a comma between a main clause and a subordinate clause (like the one starting with bevor). English is often more relaxed about this, but in German, this comma is a strict rule.