أسئلة المشاهدينTo view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video2013/3/31٣١ مارس ٢٠١٣Maria Aguirre aus Quito (Ecuador) fragt: Kann die Wissenschaft Motoren leiser machen?https://p.dw.com/p/187Cuإعلان