"When you have a situation like this occur, you are bound to have a situation down the line where there could be a shortage in food, which can also trigger other negative situations, such as malnutrition, for example, or insufficient food for cattle, which is also another important economic sector in West Africa,".

VOA: standard.2009.09.08

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

So the allowed values for m sub l 0 are going to be negative l, all the way up to 0, l and then up to positive l.

所以m小标l的可能值,是从负l，一直到，然后到正。

麻省理工公开课 - 化学原理课程节选