这个节日展示挑战主流传统的边缘戏剧作品。

The festival showcases ___fringe theatre productions that challenge mainstream conventions.

社会常常边缘化具有非传统信仰和生活方式的边缘群体。

Society often marginalizes ___fringe groups with unconventional beliefs and lifestyles.

由于激进的性质，她的观点在主流学术界被视为边缘。

Her ideas are considered ___fringe in mainstream academia due to their radical nature.