The sound is virtually undetectable to the human ear.

这声音实际上是人耳难以听得到的。

《牛津词典》

Look, it says here that the noise from it should be undetectable by other people.

看，这里说的是它发出的声音应该不会被其他人察觉。

youdao

Worse still, such ploys are often undetectable.

更糟糕地是，这样的伎俩往往探测不到。

youdao

It was Galileo's job, you'll remember, with his telescope to detect the otherwise undetectable spots and imperfections in this seemingly, but only seemingly, perfect moon.

你们还记得，通过望远镜，观测到这个看起来，却只是看起来完美无缺的,月亮上的黑点和缺陷，是伽利略要做的。

耶鲁公开课 - 弥尔顿课程节选

So Plato could still insist things that are invisible in the sense of undetectable can't be destroyed.

所以柏拉图仍旧可以坚持说无形的东西,无形这里指不能检测到,是不能毁灭的。

耶鲁公开课 - 死亡课程节选

But if we give 4 while we read invisible as meaning utterly undetectable, it's no longer so clear to me that 5 we can give him 5.

但是如果我给出,把无形理解为完全检测不到，我认为,就不能给出。

耶鲁公开课 - 死亡课程节选

Noni juice, he claims, activates xeronine--but in such small quantities, he concedes, that it's virtually undetectable.

FORBES: Tale of the South Pacific

Muia also suggested the treatment Williams received in prison had made his HIV undetectable.

WSJ: Lawyer: NY man at center of HIV scare not positive

And delivering genes directly to muscle cells might be risky, but it also would be undetectable.

FORBES: What's The Human Speed Limit?