German phrase
~ müssen von ~ begleitet werden.
Meaning
___ must be accompanied by ___
When to use it
It states a required escort. It often applies to trips or school events.
Example dialogue
Wie viele Begleitpersonen brauchen wir für den Ausflug?
How many supervisors do we need for the trip?
Alle Schüler müssen von Lehrern begleitet werden.
All students must be accompanied by teachers.