The heater is on, it's producing heat until a negative signal is registered, 'oh we've gone too high', and then it turns off.

加热器会开着,一直产生热量直到它得到一个关闭的信号,噢我们弄得太热了,然后就关闭了

耶鲁公开课 - 生物医学工程探索课程节选

I would just say that in my experience you really have to want to do this, I would definitely encourage people to be aware of the breath and try to be mindful, but remember too it's very difficult for us to leave the negative feelings.

我只想说,根据个人经验，确实要真心想这么做，我肯定会鼓励大家,留意自己的气息，并尝试着留心察觉，但让我们抛下负面情绪,也非常困难。

普林斯顿公开课 - 人性课程节选

Initially a psychoanalyst, trained through the works of Freud, she realized the focuses had been too much on the negative-- on neurosis, on psychosis and said we also, not only but also have to focus on what is working on human organism.

她最初是精神分析学者，学习弗洛伊德的理论，意识到其过于注重消极面-,神经症，精神病，她认为，还必须关注影响人类生命体的东西。

哈佛公开课 - 幸福课课程节选

But since it is a component it can have a direction, too, so can go up l between negative l and positive l.

但因为它是个分量,它是有方向的，所以它可以,从负的l一直到正的。

麻省理工公开课 - 化学原理课程节选