Jennifer Bemisderfer says this involves thinking about a product's whole lifetime: "When those products are at the end of their useful life, how are they going to be broken down?

VOA: special.2010.01.26

I can't tell you in a useful way what it is that your goals in life should be or whatever.

我也不能告诉你,你人生目标应该是什么

耶鲁公开课 - 博弈论课程节选

And you're telling them about what's useful in life, what you need to do in life.

你在告诉他们生活中什么是有用的，什么是你们必须做的。

It's important 课堂 - SpeakingMax英语口语达人

She says health facilities are a fundamental part of community life and it is important they are designed to be useful in case of emergency.

VOA: standard.2009.10.14

So some parents now are choosing to save the cord blood, have it frozen, locked away somewhere just in case its useful to their child later in life.

一些父母现在选择保存脐带血,冷冻储存起来,保存在某个地方以防万一,也许孩子将来用得着

耶鲁公开课 - 生物医学工程探索课程节选

Even small changes in what we eat and how we prepare our food can be very useful, says physician David Servan-Schreiber, author of "Anti-Cancer, A New Way of Life".

VOA: standard.2010.02.23

- And it's worth--; it's sort of a useful test for asking yourself -- what are the things you must value in life-- to ask, what would you choose to do if you knew you had five years, ten years, ? what have you?

而这值得;,这算是一种很有用的测试,用来问自己什么是你在生命中必须珍惜的事-,问你会怎么选择,如果你知道自己还有5年，10年，之类的时间？

耶鲁公开课 - 死亡课程节选

The other thing about it is that you could make lots of things that are new but generally you think of engineers as making things that are not just new but they're useful, that they do something that needs to be done, and that they do something that improves life, the quality of life of people.

另一个区别是,科学家会做很多很多新鲜玩意儿,而一般来讲,工程师做的东西不只是新奇,它们还很有用,他们做那些需要做的东西,他们做的东西能够提高,人类的生活水平和生活质量

耶鲁公开课 - 生物医学工程探索课程节选