Repairs are necessary to strengthen the bridge.

这座桥需要加固。

《牛津词典》

Thus some very dangerous drugs are approved because they are necessary to treat serious illnesses.

因此一些非常危险的药物被批准，因为它们是治疗严重疾病所必需的。

youdao

The dancers in these ceremonies wear masks, headdresses, and costumes that they believe are necessary to influence gods.

参加这些仪式的舞者戴着面具、头饰和服饰，他们认为这些是影响神的必要条件。

youdao

He also explained that he thinks more troops are necessary to support the country's nascent police and military.

VOA: standard.2009.09.29

Because they've made many copies of their genome and they've made all the proteins that are necessary to - for assembly of a new virus, then this cell can make many new viruses.

因为病毒制造了大量病毒基因组的拷贝,和所有,新病毒组装所需的蛋白质,所以这个细胞就有能力制造大量新的病毒

耶鲁公开课 - 生物医学工程探索课程节选

All of these three things, in my judgment, are necessary to understand how the polis came into being, how it came to be what it was, and how it came to fulfill and believe in these ideas that I have just been telling you about.

所有这三个事情,在我看来,对于了解城邦是如何产生,如何成型,以及如何实现,和验证那些我刚刚,告诉你们的理念,是不可或缺的

耶鲁公开课 - 古希腊历史简介课程节选

These amendments are necessary to reflect correctly policies assumed in the FY 2014 Budget.

WHITEHOUSE: Letter -- Fiscal Year 2014 Budget Amendments

We will take whatever steps are necessary to protect Caster's right to compete without restriction.

CNN: Semenya's lawyers say they will protect her right to race

In these layers, scientists are looking for organic molecules, which are necessary to create life.

CNN: Rover Curiosity near Mars landing