So, we'll take a little bit of a step back after we introduce quantum mechanics, and talk about light as a wave, and the characteristic of waves, and then light as a particle. And one example of this is in the photoelectric effect.

等我们介绍完量子力学后,我们要回过头来讨论下光,作为一种波和它的波动性特征,以及光作为一种粒子,其中的一个粒子就是光电效应。

麻省理工公开课 - 化学原理课程节选

And so, we have to step back and ask why to us do we find chocolate appealing?

所以，我们需要追溯回去,问自己，为什么觉得巧克力诱人？

耶鲁公开课 - 心理学导论课程节选

So, what we say here is we need to take a step back here and come up with an approximation that's going to allow us to think about using the Schrodinger equation when we're not just talking about hydrogen or one electron, but when we have these multi-electron atoms.

所有我们这里要说的是,我们需要退回一步,做一个近似,那样可以使我们用,薛定谔方程来考虑,让我们不是仅仅在讨论氢原子或者,一个电子的时候，而是多个电子的原子。

麻省理工公开课 - 化学原理课程节选

It was a great round shield about three feet across and it had--let me step out here so that I can show you. Can you hear me back there?

它是一块直径大概有三英尺的巨大圆盾,恩,它还有...我出来演示吧,这样你们就能看清楚,能听到我说话吗

耶鲁公开课 - 古希腊历史简介课程节选

So, anyway, that writing--let me back up a step.

好吧,那些文字...我们先从早的开始说

耶鲁公开课 - 古希腊历史简介课程节选

And so we need to step back.

所以我们需要追溯回去。

耶鲁公开课 - 心理学导论课程节选

They come so instinctively and easily it's difficult, and sort of unnatural, to step back and explore them scientifically but if we're going to be scientists and look at the mind from a scientific perspective we have to get a sort of distance from ourselves and ask questions that other people would not normally think to ask.

他们来得如此本能，容易,这是困难的，有某种超自然韵味，退后，从科学角度研究他们,但如果我们打算成为科学家,从科学角度,看待心理,我们需同我们自身保持某种距离,问问题,问其他人通常不想问的。

耶鲁公开课 - 心理学导论课程节选