Swan is optimistic that humans can take the necessary collective steps to address climate change and put the brakes on global warming.

VOA: standard.2009.12.10

For, as Rutherford has shown the assumption of the existence of nuclei, as those in question seems to be necessary in order to account for the results of the experiments on large angle scattering of the alpha rays.

因此卢瑟福,提出了原子核存在的假设，这些关于问题的假设对于,解释阿尔法粒子的,大角度散射是有必要的。

麻省理工公开课 - 固态化学导论课程节选

If people are on the verge of dying, perhaps it is necessary to overlook that injustice, but I think it's important to keep in mind that we're still committing injustice by taking people's belongings or assets.

如果人们在死亡边缘挣扎，也许忽视这样的不公平是必要的，但我认为即使这样，我们依然要铭记,我们的行为不公正,这是在占有他人的财物或资产。

耶鲁公开课 - 公正课程节选

He says it may be necessary to call on the Association of Southeast Asian Nations to mediate an end the diplomat dispute.

VOA: standard.2009.11.11

All of our texts that we will read--the Republic the Politics the Prince the Social Contract have different views on the qualities of statecraft and what are those qualities necessary to found and maintain states that we will be considering.

我们所有将阅读的教材中，包括《理想国》,《政治论》，《君主论》，《民约论》,都有不同的权术特性观点,哪些特性是建立及维持国家所必需,我们都将加以思量。

耶鲁公开课 - 政治哲学导论课程节选

The government insists bans on rallies and hundreds of arrests have been necessary to prevent large gatherings that intelligence agencies believe will be attacked.

VOA: standard.2009.03.14

But what the White House sees as a necessary,thoughtful process to arrive at the best-possible decision on an eight-year conflict is seen as dangerous "dithering" by Republican legislators.

VOA: standard.2009.11.23

That accord mandated by the U.S.Congress is a necessary prerequisite for American aerospace firms to bid on a pending Indian purchase of 126 multi-role fighter jets, potentially the largest-ever arms sale.

VOA: standard.2009.07.20

"The focus of that dialogue is on Iran's behavior and uppermost in our minds is taking the measures necessary, with our partners in the region, to maintain their security and their stability,in particular against Iranian subversive activities,"

VOA: standard.2009.05.05

"The Temple Mount was open to Muslims that wanted to come and pray only from the age of 50 upwards, and women of all ages, This was necessary to prevent any disturbances from taking place on the Temple Mount."

VOA: standard.2009.10.05

Their task is to find common ground, including on reduction of greenhouse gas emissions, promotion and transfer of new more eco-friendly technology and the necessary funding to make this possible, especially for the less developed and poorer nations.

VOA: standard.2009.12.08

Speaking via Skype,she says no. "I think further studies will be necessary to show whether the differences we've demonstrated depending on delivery mode of babies when they first emerge into the world actually carry over time, and whether those differences might contribute to health outcomes."

VOA: standard.2010.06.30

"Black women, who are more likely to be uninsured, are living in communities where there is limited access to the healthy foods and exercise and activity that is necessary from childhood on to reduce the likelihood of obesity and chronic illnesses."

VOA: standard.2010.06.23

"The delivery of capability here in Haiti is a balancing act that requires troops on the ground to distribute humanitarian assistance, the supplies for them to distribute and the mobility necessary for them to be able to reach the communities that are most stricken,".

VOA: standard.2010.01.19