一息尚存

一息尚存是逞活着，息是氣息、呼吸，存是在、有。
一息尚存 means still alive. 一息 is one breath. 尚存 is still exist.

一差二錯

一差二錯是疏漏或差錯。
一差二錯 is describe a couple mistakes, overlooking or doing something wrong. 一差 is one difference, 二錯 is two mistakes.

一哄而散

一哄而散說的是一嚷就散了，只須喊一聲，所有人都走了。
一哄而散 describe how fast the group is disintegrated. Just a shout, everybody is gone. 一哄 one scream or shout, 而 then 散 fly away, broken into pieces, meaning all gone.