Among the indiscernibles are absolute space, time and direction.

人类至今尚未认识的事有绝对的空间、时间和方向。

The transition was almost indiscernible.

那转变几乎不能察觉。

The historical development of a language is hardly a sudden transformation of one language into another, but a gradual and constant process, often indiscernible to speakers of the same generation.

语言变化是一个缓慢的渐变的过程，其变化是同代人所不易察觉的。