Why "чи" which is translated as "or" in all other examples in this course, when "якщо" has been introduced a few lessons ago as "if".
Ми не знаємо якщо це правда?
In theory you can use 'чи' as a condition: if, whether etc. The corret translation of 'or' is "або" - the choice between (something, someone). But you would be understood in both cases.