You have to be good but not an expert at everything you do, and you have to know when to be flexible and when to ask for help.

你不需要事事都是专家，但是必须事事都能做好，并且你得知道什么时候灵活多变，什么时候寻求帮助。

youdao

The best way is to know when to speak and when to be silent.

最好的方法就是知道何时说话，何时闭嘴。

youdao

The light signals sent to your body's master clock tell you when to be sleepy and when to be alert.

传送到我们身体的主时钟的信号告诉我们什么时候该睡觉，什么时候又该打起精神。

youdao

There used to be a time when the quickest way to travel across the western United States was in a stagecoach.

VOA: special.2010.04.26

So, at any rate, this seemed to me to be, when I started teaching this course, reasons not to teach it.

因此无论如何对我来说，当我开始教这门课的时候决定不说它的原因。

耶鲁公开课 - 现代诗歌课程节选

But the one that they do now... I would be there to see when the wrestlers come in, at the back entrance.

但是他们现在做的这种……当摔跤手进来时，我会在后门那里看着。

麦迪逊广场花园 - SpeakingMax英语口语达人

He knows just when to be cryptic, peremptory, encouraging, and so on.

NEWYORKER: Playing The Numbers

While some companies are letting customers create their marketing, others are toying with letting them decide when to be marketed to--and by whom.

FORBES: Magazine Article

By being prepared with facts and understanding their negotiation position, expert negotiators know when to make a strong bargaining move, and when to be softer.

FORBES: Flourish As An Influential Leader - Think Like A Negotiator