These cells are rare and so it's been hard to identify them, that's part of it.

这些细胞太少了,所以很难找到,这是原因之一

耶鲁公开课 - 生物医学工程探索课程节选

And finding actors who can really take your characters and bring them to life is very rare.

而且能够真正演绎你创造的角色，并把他们演得活灵活现的演员确实很少。

灵感从何处来 - SpeakingMax英语口语达人

You have a full monarchy in the sense that both-- we in America talk about the separation of church and state, that is a very rare and unusual thing in the history of the world.

他有一个完全政教合一的君主政权,在美国政教是分离的,这在世界历史上很少见

耶鲁公开课 - 古希腊历史简介课程节选

It is a rare person who couldn't stand up there and everybody would figure out what they're lying about, but the transparency effect is we don't feel that way.

很少有人会站在这里,让大家都猜出他们撒了什么谎，但因为透明效应，我们并不这样觉得。

耶鲁公开课 - 心理学导论课程节选

And, in a rare moment of sort of personal self-reflection or self-reference, he notes somewhat drolly that the novelty of his ideas will make it difficult for them to find an audience.

虽然他很少对自己的思想,进行自我反思或自我参照，但他还是自嘲地写道,那些新奇的思想会让它们,很难找到读者。

耶鲁公开课 - 政治哲学导论课程节选

In rare, but not unheard of, cases, some people begin to have those unusual biological processes and then return to the normal biological processes and can talk about what was happening in the unusual biological processes.

在少见,但并非从未听闻的,情况下,有些人开始,经历那样一些不正常的生理过程,然后回归正常的生物学过程,他们可以谈论,在那个不正常的生物过程里发生了什么

耶鲁公开课 - 死亡课程节选

One reason it's been harder to identify stem cells is that they're so rare; the other reason is that it's hard to identify the characteristics of them and it's taken many years to work this out.

干细胞难以识别的原因之一是,这些细胞很少,另一个原因就是,干细胞的特征性蛋白难以识别,我们花了好多年去解决这个问题

耶鲁公开课 - 生物医学工程探索课程节选

It's perfectly fine, but they envy us for our finite lifespans, because what we've got and they don't have is something that's for each individual rare-- something that's not lasting, something that's precious in that way.

不朽很好，但他们羡慕我们的有限寿命，因为我们有而他们没有的是,对每个人来说稀有的东西-,不会永远持久的东西，从那个层面讲珍贵的东西。

耶鲁公开课 - 死亡课程节选