And that if we want a positive earth for future generations, we all need to make commitments to be change agents so that we don't destruct our natural resources."

VOA: special.2010.01.21

No, we call that work positive work. All right, so that means we need to put a negative sign right here, by convention.

历史上有过不同的习惯，这里我们规定,如果环境对系统做功。

麻省理工公开课 - 热力学与动力学课程节选

And we haven't talked about reactions at all yet, so you don't need to worry about the specifics of that exactly, but just that if you have this negative change in energy, you have a more stable product than you do reactant.

当然我们还没有开始讨论反应，所以你不用担心它的细节是怎么样的，你只需要知道，如果能量的变化是负值，那么你将得到一个比反应物更稳定的生成物。

麻省理工公开课 - 化学原理课程节选

These things are all very important drivers of the diet, so we need to know what's happening globally.

这些对饮食导向都有着重要的影响,所以我们要知道世界范围发生的事情

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

So to explain all this we need now a sort of crash course in Plato's metaphysics.

要解释这些,我们现在得恶补一点柏拉图的形而上学

耶鲁公开课 - 死亡课程节选

So all we need to find out is the work now.

所以我们现在需要知道的。

麻省理工公开课 - 热力学与动力学课程节选

Right, so to get all the way, good, so to get all the way, thank you So to get all the way to 1, we need a lot.

没错,所以这样一来,很好,所以这样一来,谢谢你,要让平均数到1需要很多条件的

耶鲁公开课 - 博弈论课程节选

Well, what's nice about this program is that there's just one function, main, so we don't need to draw the stack and get things all complicated.

这个程序的优点是,这里只有一个函数main，这样我们就不需要,画出堆，也不用那么复杂。

哈佛公开课 - 计算机科学课程节选

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

So for example, if we think about fluorine, 1 s 2 2 s 2 2 p 5 that has an electron configuration of 1 s 2, 2 s 2, 2 p 5, so all we would need to do is add one more electron to get the same configuration as for neon.

比如，如果我们考虑氟原子的话，它的电子排布是，因此我们所需要做的就是给它加上一个电子,使得它与氖原子的电子排布相同。

麻省理工公开课 - 化学原理课程节选

All right, so, what we need to ask ourselves, then, is, "What about the soul?"

那好,现在我们要问问自己,灵魂是什么

耶鲁公开课 - 死亡课程节选

But we've been so completely socialized into thinking two things: one is that we need water with us all the time; and second we have to buy it.

但如今我们都对以下两个观念习以为常了,第一是我们每时每刻都需要水,第二是我们要花钱买水

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

px 2py So we need to fill all the way up to the pi 2 p x, and the pi 2 p y.

我们需要填到。

麻省理工公开课 - 化学原理课程节选

So, in terms of finishing our Lewis structure, we're actually not done yet here, even though we have full octets, and we've used up all of our valence electrons, and the reason is because it's c n minus, so we need to make sure that that's reflected in our Lewis structure, so let's put it in brackets here, and put a minus 1.

那么，根据我们的路易斯结构的完成情况，我们实际上还没有全部完成，尽管我们有了填满的“八隅体“,而且用完了所有的价电子，原因就是因为这是一个负离子，我们需要确保我们的路易斯结构能反映出这一点，所以让我们给它加个括号，再加个负一。

麻省理工公开课 - 化学原理课程节选