化学物质的蒸发对它们的生存是必不可少的。
The evaporation of chemicals is necessary for their survival.
对于人们来说，发明是至关重要、必不可少的，正如灵魂对人们来说是不可或缺且意义重大的一样。
Invention is momentous and fundamental to people what the soul is vital and significant to us.
对前几代人来说，大学是摆脱父母控制的一个决定性时期，同时同龄人和长者的支持与指导也是必不可少的。
For previous generations, college was decisive break from parental control; guidance and support needed help from people of the same age and from within.
另一个问题是，一组细菌对人体的基础生理是否是必不可少的；换言之，人类是否真的是没有共生菌就会死的共生体。
Another is whether a set of bacteria is essential for basic human physiology-in other words whether humans really are symbiotic creatures who would die without their collaborators.
对我们开发工具而言，反馈是必不可少的，任何来自社区的反馈或建议都是我们的无价之宝。
Feedback is essential for us working on developer tools, and so any feedback or suggestions from the community are absolutely priceless to us.
事实上，对任何行动与回报联系一起的东西来说，“多巴胺都是形成这些习惯必不可少的东西，”沃尔寇说。
In fact, for anything that links an action and a reward, "dopamine is indispensable for the formation of these habits," Volkow says.
初级生产、加工、分发和销售中良好的控制与操作，对安全食品的生产来说都必不可少。
Good controls and practices during primary production, processing, distribution and sale are all essential to the production of safe food.
蒂莫西先前是美联储纽约银行的行长，他说这一计划对美联储工作人员来说是额外增加的但也是必不可少的。
Mr. Geithner, who before joining the administration was head of the Federal Reserve Bank of New York, has said the administration’s plan for the Fed is both incremental and essential.
其主要目标是在保持关注点分离的同时，为构建企业集成解决方案提供一个简单的模型，该模型对产出可维护、可测试的代码来说是必不可少的。
Its primary goal is to provide a simple model for building enterprise integration solutions while maintaining the separation of concerns that is essential for producing maintainable, testable code.
这些活动意义重大，因为它们对我们塑造的丰富多彩的生活必不可少。
These activities are profound in the sense that they are essential to what we characterize as a flourishing human life.
磷对人体中健康的皮肤，头发和神经必不可少。
即便是对唯一靠谱的西班牙血统的竞争者—空客军用C- 295—而言，这似乎也是必不可少的。
This seemed essential, even though the only feasible competitor - the Airbus Military C-295 - was of Spanish origin.
至于巴勒斯坦人的团结，这实际上对任何切实可行的解决方案都是必不可少的。
As for Palestinian unity, it is indeed essential for any viable settlement.
短数据库事务对任何高性能、高可扩展性的应用程序来说都是必不可少的。
Short database transactions are essential for any highly performing and scalable applications.
书中对她的描写只是一笔带过：对她的一句评论，一种看法，太多的阅读之旅中她那必不可少的身影。还有她越来越孱弱的身体。
She is glimpsed in flashes, a remark, an insight, an indispensable presence on too many reading Tours, increasingly ill.
对很多用户来说，LinkedIn的确已经成为职业生涯道路上必不可少的工具，但不会每天或每月都使用该网站。
For many people, it became an indispensable tool for certain moments of professional panic, but not something you used daily or even monthly.
性别平等对实现增进健康是必不可少的。
Gender equality is essential to the achievement of better health.
一定程度的暴露于阳光对健康是必不可少的——只有过分的暴露于阳光才会导致皮肤灼伤受损。
Some exposure to the sun is necessary for health - it is excessive exposure leading to burning of the skin that does the damage.
日光和新鲜空气对身体健康是同样必不可少的。
Sunlight is no less necessary than fresh air to a healthy body.
大多数这些微生物不会引起任何问题，而且许多微生物，像那些通常寄生在消化道并产生维持生命的养分的微生物，对良好的健康是必不可少的。
Most of these micro-organisms cause no problem, and many, like the ones that normally live in the digestive tract and produce life-sustaining nutrients, are essential to good health.
它们是必不可少的，不仅仅是对单个的用户，对整个社会也是，因为它们通过分享与合作促进了整个人类社会的团结和休戚与共。
They are essential, not just for the individual users' sake, but for society as a whole because they promote social solidarity-that is, sharing and cooperation.
英国内政大臣特雷莎梅在宣布新举措时说：“我认为会说英语对每个想在英国定居的人来说都必不可少。”
"I believe being able to speak English should be a pre-requisite for anyone who wants to settle here," said Home Secretary Theresa May, announcing the new measures.
但是对一个组织的日常活动来说“交流，也就是交换讯息，观点和知识对作出正确决策必不可少。”
But in the everyday life of an organization, "communication-sharing of information, perspectives, and knowledge-is essential to making good decisions."
首先，考虑对中枢神经的报偿机制的最新研究进展的了解是必不可少的。
First, it is imperative that recent advances in the understanding of neural reward pathways be considered.
由于佐剂具有其自身的药理学特性，可能会影响疫苗的免疫原性和安全性，因此对其进行安全性评估是必不可少的。
Since adjuvants have their own pharmacological properties, which might affect both the immunogenicity and the safety of vaccines, safety assessment is essential.
由于佐剂具有其自身的药理学特性，可能会影响疫苗的免疫原性和安全性，因此对其进行安全性评估是必不可少的。
Since adjuvants have their own pharmacological properties, which might affect both the immunogenicity and the safety of vaccines, safety assessment is essential.
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