One reason is that they're present in very small numbers.

一个原因就是它们的数量非常稀少

耶鲁公开课 - 生物医学工程探索课程节选

A person, a place or a thing that's related to something that you're talking about in the present moment.

你可以谈论与当前的情景相关的人物、地点或者事物。

remind me of 课堂 - SpeakingMax英语口语达人

Self-alienation, in Barth's work, is the product of desire. Desire, love: that's the moment when you're supposed to be perfectly present.

巴斯作品中，自我疏离是欲望的产物，欲望，爱：,那是你应该在场的时刻。

耶鲁公开课 - 1945年后的美国小说课程节选

So for all of our customers who speak Spanish around the world, we now have a community forum where our customers can comment, our people inside the company can present ideas and new things that we're doing.

所以对于我们全世界,说西班牙语的客户来说，我们有了一个社区论坛,提供了评论的平台，公司内部人员也可以,交流新的想法。

斯坦福公开课 - 戴尔CEO-Michael.Dell谈创业和发展课程节选

They're not actually present in the real world of Milton's hell, or if it's a pagan god who's mentioned, Milton will tell us that the pagan god was just an early manifestation of one of the fallen angels.

事实上他们没有在弥尔顿笔下的地狱中出现，或者作为异教的神被提及，弥尔顿将告诉我们那些异教的神只是堕落天使中,一名天使早期的表象。

耶鲁公开课 - 弥尔顿课程节选

Those animals that you produce are called transgenic animals because they're expressing, usually at high levels, a transgene or a gene that's not normally present in their species.

那么这些小鼠就称为转基因动物,因为转基因动物,通常能高效地,表达转基因,即一个通常不存在于该物种的基因

耶鲁公开课 - 生物医学工程探索课程节选

But-- as my team was in the Michigan State game last Saturday, with me present, a very sad person you're looking at-- he was blown out, and on September 4th, 1870, there is yet another insurrection in Paris.

但是...,就像我们组上周六去参加密歇根州运会那样,就是因为有我这样的队员,有我这样的衰人参加...,他被打得满地找牙,在一八七零年九月四日,巴黎发生了另一场起义

耶鲁公开课 - 1871年后的法国课程节选