树木起天然的保护作用，遮挡了阳光的照射。

The trees form a natural protection from the sun's rays.

《牛津词典》

这堵墙挡着常刮的风，起到一些保护作用。

The wall gives some protection from the prevailing wind.

《牛津词典》

研究发现适量饮酒有很强的保护作用。

The research found moderate drinking has a strong protective effect.

youdao

It's great because there's huge expectation that we are gonna bring this agency back, that we are gonna restore EPA with places, the protector of air, water and land.

这么做很好，因为人们期待着,环境保护署重新回到视线当中，期待环境保护署能够重新，发挥对大气，水以及土地资源保护作用。

普林斯顿公开课 - 领导能力简介课程节选

So that they will want to conserve the wilderness." That's what it was about.

这样他们就会想要保护这片荒野。”那就是它的作用。

美国的博物馆教育 - SpeakingMax英语口语达人

You have to inject it multiple times because the first blip that you get in immune response is not very high, you have to boost and often you have to boost again in order to get a high enough response to be protected.

你必须得进行多次注射,因为第一次注射,无法使免疫系统产生强烈反应,你得要增强免疫,通常还得再增强一次,以使反应足够强烈,从而起到保护作用

耶鲁公开课 - 生物医学工程探索课程节选