Questions & Answers about Muszę być w biurze na siódmą.
Muszę means I must / I have to. It comes from the verb musieć (to have to / must).
In Polish, after musieć, you normally use another verb in the infinitive:
- muszę być = I have to be
- muszę iść = I have to go
- muszę pracować = I have to work
So Muszę być w biurze... literally means I have to be in the office...
Because Polish often leaves out subject pronouns when they are clear from the verb form.
- muszę already means I must
- so ja muszę is possible, but usually unnecessary
You would add ja only for emphasis or contrast:
- Ja muszę być w biurze, ale ty nie.
I have to be in the office, but you don’t.
So the sentence is completely natural without ja.