Learn German: Die Wohnung muss dringend renoviert werden. - The apartment urgently needs to be renovated.

When you use a modal verb like muss in a main clause, it takes the second position and pushes the rest of the verb phrase to the very end. For the passive voice, that means the past participle (renoviert) goes to the end, immediately followed by the passive helper verb (werden).

Why is werden in its infinitive form here instead of being conjugated?

The modal verb muss is the reason! Modal verbs always force the final verb in the clause into the infinitive. In a regular passive sentence without a modal, werden is conjugated (e.g., Die Wohnung wird renoviert). But when you add a modal, it takes over the conjugation, and werden reverts to its infinitive form.

Why doesn't the past participle renoviert start with a ge- prefix?

Verbs that end in -ieren (like renovieren, fotografieren, or studieren) are an exception to the normal past participle rules. They never take the ge- prefix. You just take the verb stem and add a -t at the end to make it a past participle.

The English translation uses "needs to be", but the German uses muss (must). Why?

While müssen literally means "must" or "to have to", "needs to" is often the most natural way to express this level of necessity in everyday English. Saying "The apartment must be renovated" is also a perfectly valid translation, just a bit more formal.