And what we saw last time is that this was necessary to make things work, this part of it in particular.

上节课我们讲,这是对外做功的必要条件，特别是这个部分。

麻省理工公开课 - 热力学与动力学课程节选

The fact that I have this star here, this star here, this star here, is really just 'cause I'm a little anal and it looks pretty to make a little box out of everything but it's not strictly necessary.

事实上大家可以看到，这有颗星，这有颗星，这有颗星，其实是我手痒,这看起来像是用*围成个框，把它们包围起来,其实这是完全没有必要的。

哈佛公开课 - 计算机科学课程节选

Why is it necessary to rend something, to make it soul or whole? Is it necessary?

为什么要撕破某样东西，它才能完美呢，这有必要吗？

耶鲁公开课 - 现代诗歌课程节选

That is to say a certain diversity is necessary to make up a city.

也就是说,某些差异是组成城市所必备。

耶鲁公开课 - 政治哲学导论课程节选

Because they've made many copies of their genome and they've made all the proteins that are necessary to - for assembly of a new virus, then this cell can make many new viruses.

因为病毒制造了大量病毒基因组的拷贝,和所有,新病毒组装所需的蛋白质,所以这个细胞就有能力制造大量新的病毒

耶鲁公开课 - 生物医学工程探索课程节选