它只在血液流动较缓的静脉中起作用。

It works only in the veins, where the blood flow is slower.

《柯林斯英汉双解大词典》

它获取植物在光合作用过程中产生的能量，光合作用是一个将太阳光转化为植物自身能量的过程。

It captures the energy which plants produce during photosynthesis—a process of converting sunlight into energy.

youdao

他们认为，它应该用来保护个人权利和公共自由，在个人的努力无效时，它具有特殊的作用。

They believed that it should be used to protect individual rights and public liberty, and that it had a special role where individual effort was ineffective.

youdao

That played a powerful role in my life in terms of connecting faith and social justice for me. -Right.

那在我的生活中发挥了强大的作用,它帮助我将信仰和社会正义相连，-对。

普林斯顿公开课 - 人性课程节选

If you connect the body to a spring, which is neither compressed nor extended, there's no force acting on it.

如果将一个弹簧连在这个物体上,弹簧既没有被压缩也没有被拉伸,也不会有力作用在它上面

耶鲁公开课 - 基础物理课程节选

They're making that because you need this protein insulin, it's a hormone, and it's important for sugar metabolism in your body.

它们产生胰岛素蛋白是因为你需要它,胰岛素是一种激素,它在糖代谢中起着非常重要的作用

耶鲁公开课 - 生物医学工程探索课程节选