Daily Chinese Idiom Guessing Game
Refers to major issues of principle, where right and wrong are clearly defined.
指带有原则性、根本性的是非问题。
徐迟《歌德巴赫猜想》一页一页的历史写出来了，大是大非，终于有了无私的公论。”
In matters of 大是大非, we must not compromise our principles.