Piper's prime function here is wildlife control.

他的首要任务是驱赶野生动物。

Hair's prime function is for thermo-regulation and it played a very vital part when our ancestors came from forest-like environments, helping to keep heat in, when it got too hot, it kept heat away.

毛发的主要功能是调节温度，当我们的祖先来自类似森林的环境时，它发挥了非常重要的作用，帮助保持热量，当天气变得太热时，它会把热量带走。

This is a function of the primary-school teacher which our fathers never thought of, but which every passing year brings out more and more clearly as a prime function of every instructor of little children.

这是我们的父亲从未想过的小学教师的职责，但随着时间的推移，它越来越清楚地成为每位幼儿教师的主要职责。