如果这辆汽车需要清洗，你还在等什么呢？

If the car needs cleaning, what are you waiting for?

《牛津词典》

如果你需要再和我联系，这是我的名片。

Here's my card if you need to contact me again.

《牛津词典》

你需要一口带有蒸笼的锅，如果没有就临时凑合一下。

You need a wok with a steaming rack for this; if you don't have one, improvise.

《柯林斯英汉双解大词典》

It's very exciting, but if you think you know everything you don't need to learn, you don't belong to us. I always need to learn.

这很令人兴奋，但如果你认为,你什么知道，你不需要学习了，那么请你退出百度，因为人总是在学习。

斯坦福公开课 - 百度CEO李彦宏演讲：全球最大搜索引擎的发展课程节选

You guys have to decide whether you, okay. So if you're going to, if you're running you stand up.

你们需要考虑是否你们,这么说吧,如果你们要,如果你要参选,你就站起来

耶鲁公开课 - 博弈论课程节选

And I'm sure you can imagine that if you want to label onw protein green and one red and one yellow, now you can start looking at really complex biological processes.

我相信你们可以想象如果你,需要把一个蛋白质标记成绿色,一个标记红色，一个标记黄色，这样你就可以研究非常复杂的生物学过程。

麻省理工公开课 - 化学原理课程节选