然而，我们能够觉察到它的踪迹。

However, we can detect traces of it.

youdao

你没有觉察到它的到来，并且它一旦开始就没有办法摆脱。

You don't see it coming, and there's seemingly no way to get rid of it once it starts.

youdao

核辐射这种现象多少有点神秘，其部分原因是人类的官能无法觉察到它的存在。

Nuclear radiation has a certain mystery about it, partly because it cannot be detected by human senses.

youdao

We can detect radio waves on the basis of their affects.

我们可以根据它的影响,觉察到无线电波。

耶鲁公开课 - 死亡课程节选