1.worry about 焦虑…；担心…

I have nothing to worry about in this life.
我这一生都很省心。

Today he does not have to worry about making a living.
现在他不用为生活发愁了。

2.demand for 要求

Extensive advertising can cause a factitious demand for an article.
大规模的广告宣传能引起对某一商品的反常需求。

This massive investment indicates that there is demand for virtualization of resources inside the cloud.
这样巨大的投资表明，对云中资源的虚拟化存在着巨大的需求。

3.prevent from 阻止，制止

To prevent and investigate illegal activities; to attack and take precautions against terrorism; to maintain the public order and prevent from activities against public order.
预防、制止和侦查违法犯罪活动；防范、打击恐怖活动；维护社会治安秩序，制止危害社会治安秩序的行为。

Ridgewell calculated that, with current carbon prices, farmers could earn 23 euros per hectare for the CO2 they prevent from reaching the air.
Ridgewell的计算结果指出，按照当前的碳价，农民们将因他们在控制碳排放上的贡献从每公顷土地上得到23欧元的回报。