"Big ears, big old jug ears like that." Pett says,cartoonists are essential to showing the lighter side of life, especially in difficult times.

VOA: standard.2010.03.20

These proteins have functions that are essential for life of the cell, they transport molecules back and forth across the membrane.

这些蛋白所起的功能,对于细胞生存至关重要,它们负责转运分子通过细胞膜进出细胞

耶鲁公开课 - 生物医学工程探索课程节选

For the Greeks,on the other hand as I've said, political society was essential for living any kind of a good life.

对于希腊人,就像我说的另外一方面,对他们而言,政治社会,是人们获得幸福生活的关键

耶鲁公开课 - 古希腊历史简介课程节选

So, some sort of ability to record information and make generalizations is absolutely essential to making it through life.

所以记录信息的能力,和归纳的能力是非常重要的,是我们生存的关键。

耶鲁公开课 - 心理学导论课程节选