"Maybe the reason why free radicals and aging are correlated is because free radical production in the mitochondria (part of the cell) is a stress reaction to the damage of aging," Hekimi said.

海克米说：“人们之所以把自由基和衰老联系在一起，可能是因为自由基在线粒体(细胞的一部分)中产生是人体对衰老的应激反应。”

youdao

The cost, too, fell, because slag is free, whereas clay costs money.

因为渣是免费的而粘土需要钱，所以成本也下降了。

youdao

Gene flow is relatively free because individuals can move and then mate with individuals in their new location.

基因流动是相对自由的，因为个体可以移动，然后在新的地方与个体交配。

youdao

It was free because Congress -- in the Missouri Compromise of Eighteen Twenty -- made slavery illegal in that area.

VOA: special.2009.05.14

Only in the Roman Empire could slavery actually start being a way that you can move up in society, because you could-- if you were a talented slave, your owner might free you, probably would free you.

只有在罗马帝国，奴隶制可以成为,提高社会地位的手段，因为。。。,如果是一个能干的奴隶，主人可能会释放他，很有可能。

耶鲁公开课 - 新约课程节选

And so the energy is zero because the electron is no longer bound. It is free.

所以这个系统能量为0，因为,电子不再受束缚了，它自由了。

麻省理工公开课 - 固态化学导论课程节选

And you need to pay attention to free file, because free filing, from what I understand, is only for your federal taxes, not for your state taxes.

NPR: Tech Tips for Making Taxes Less Painful

Because free capital mobility involves risks as well as opportunities.

ECONOMIST: Time to turn off the tap?

Obama called the film "disgusting" in his address before the United Nations, but said the answer was not to ban it because free speech is protected in the United States.

CNN: 5 things we learned on second day of U.N. General Assembly