If we do not get enough of the vitamins we need in our food,we are at risk of developing a number of diseases.

VOA: special.2009.04.21

So, then all we need to do to determine which elements that corresponds to is take a look at our periodic table.

因此，我们需要做的只剩下,在元素周期表中寻找,对应的元素有哪些。

麻省理工公开课 - 化学原理课程节选

But that's a little bit hard, we aren't all that good at seeing electrons with our eyes, so we need to think of a way to do this.

但那有一点困难，我们都不能通过眼睛看到电子，我们需要想一种方法去做到它。

麻省理工公开课 - 化学原理课程节选

And notice by the by, that when we make choices about our future, from the hedonist point of view, at least, there's no particular need to dwell a whole lot on the past, because what's done is done.

需要注意的是，当我们,为未来作选择时，起码享乐主义者认为，不必过分着眼于过去，因为过去的已经过去。

耶鲁公开课 - 死亡课程节选

So, if we're talking about five different orbitals and we're talking about a ground state atom, we know that we just need to start at the bottom and work our way out up.

因此，如果我们要讨论的是,五个不同的轨道且是属于一个基态原子的话，我们知道，我们只需要从最低的轨道,开始一个一个往上找。

麻省理工公开课 - 化学原理课程节选