蝙蝠会发出我们听不到的非常高的超声波脉冲。

The bat emits these ultrasonic pulses, very high pitch sound waves that we cannot hear.

youdao

让我们来谈谈声谱的另一端，人类听不到的声音——超声波。

Let's talk about the other end of the acoustical spectrum, sound that is too high for humans to hear—ultrasound.

youdao

人们开始意识到，当你什么都听不到的时候，生活会变得多么困难。

People became aware of how difficult life could be when you can't hear anything.

youdao

I've found some people really have to come to the first and second row because they claim that if they don't hear me they cannot really go to sleep.

我发现有些人必须得在第一,二排睡觉,因为他们说如果听不到我的声音,他们就无法入睡

耶鲁公开课 - 基础物理课程节选

So when we say, he says invisible things can't be destroyed, he means the things that you can't see or touch or hear or feel, whatever it is, see, touch, smell, taste.

所以当我们说，他说无形的东西不可毁灭，他的意思是你看不见摸不着,听不见也感觉不到的东西，看，摸，问，尝所有这些。

耶鲁公开课 - 死亡课程节选

So even that wasn't loud enough okay, so we we really need to get people-- That was very clear, very nice, but we need people to stand up and shout, or these people at the back can't hear. So your name is?

这样声音还是太小,所以我希望,之前的同学的解释清晰正确,但以后请大家站起来大声点说,否则后面的听不到,你的名字是

耶鲁公开课 - 博弈论课程节选