Yeşil giymek isteğe bağlıdır.
- Wearing green is optional.
Bu, isteğe bağlı olsa da hala ev ödevini yapman gerekiyor.
- Even though it's optional, you should still do the homework.
This organization relies entirely on voluntary donations.
- Diese Organisation ist vollständig auf freiwillige Spenden angewiesen.
That organization depends on voluntary contributions.
- Diese Organisation ist von freiwilligen Spenden abhängig.