They became a symbol of the Olympic Games​.

Общий: Did they become a symbol of the Olympic Games​?

Альтернативный: Did they become a symbol or a sign of the Olympic Games​?

Разделительный: They became a symbol of the Olympic Games​, didn't they?

Специальный: What did they become a symbol of?

Вопрос к подлежащему: Who became a symbol of the Olympic Games​?