He notes that broad policy changes that reduce reliance on fuels like coal and wood are being implemented and are beginning to have a positive impact on life expectancy.

VOA: standard.2010.04.07

It was the first time a country had taken action on that, so these are very positive public health changes.

这是第一次国家政府对此采取措施,这都是些对大众健康很有益的改变

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

That's a very positive change in the food environment, so we'll talk about those sort of changes.

这是食品环境的一项积极改变,我们将会谈到这一类的改变

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

However,given that there is at least some evidence for positive effects from some of these lifestyle changes, plus other benefits apparently unrelated to cognitive decline, Burke offered some recommendations.

VOA: standard.2010.06.17

Now, what happens during an action potential is that that membrane potential changes very rapidly and it changes from being negative to being more positive.

在动作电位产生时,膜电位迅速改变,从较负的电位向更正的电位改变

耶鲁公开课 - 生物医学工程探索课程节选