And so, when you think about how much cement concrete are consumed annually on the planet, this becomes a considerable point source of greenhouse gas emissions.

当你想到,在地球上每年要消耗多少的水泥混凝土的时候,这将是温室气体排放的,一个主要来源。

麻省理工公开课 - 固态化学导论课程节选

But thankfully now in 2010, we're at the point where there's a whole lot of free and open source software that you can integrate into your projects that other nice people have made available.

不过幸好在2010年,现在有很多可用的开源,代码软件，你可以将其融合,到你的工程中。

哈佛公开课 - 计算机科学课程节选