参考答案

正确答案：fears and excuses
fears and excuses 解析：空前的by表明，本空应填一名词(短语)。题干中的fascinated to travel与第二句提到的desire to travel对应，those…are held back from traveling around the world by…与…prevent people from doing it对应，故prevent的主语fears and excuses即为本题答案。