The others perform countless useful functions in everyday lives.

其他细菌在日常生活中发挥着无数有用的作用。

Technological development is a powerful driver of economic improvement, for example, which is a useful function.

比如，技术研发常常驱动经济发展，是一个有用的“社会功能”。

Okay, right, now, here are some kind of useful functions and phrases we could use for evaluating things.

好的，这里有一些有用的功能和短语，我们可以用来评估事物。

Surely it serves some useful function.

当然它有一些有用的功能。

It serves useful functions in servicing, for example—as Tesla's long-running struggles in this area illustrate.

例如，它在维修方面发挥着有用的作用——特斯拉在这一领域的长期斗争就说明了这一点。

Its only " useful" function is that it strengthens the ego, and that is why the ego loves it.

它唯一“有用” 的功能是强化小我，这就是小我喜欢它的原因。

I think it's very interesting because languages change over time and if you look carefully, you find 'like' has new and useful functions in English.

我认为这非常有趣，因为语言会随着时间的推移而变化，如果你仔细观察，你会发现“like”在英语中具有新的而又有用的功能。

K-12 Schools also provide childcare that makes working parents’ lives easier – not the intended purpose of schools certainly, but a pretty useful latent function.

K-12 学校还提供托儿服务，让在职父母的生活更轻松——这当然不是学校的预期目的，但却是一种非常有用的潜在功能。