Onlardan birini seçebilirsin.
- You may choose one of them.
Onlardan biri bir casus.
- One of them is a spy.
If two men always have the same opinion, one of them is unnecessary.
- Wenn zwei Menschen immer die gleiche Meinung haben, ist einer von ihnen überflüssig.
One of them is lying.
- Einer von ihnen lügt.