The country's vast offshore oil and gas resources have provided the government That is a source of both hope and fear.

VOA: standard.2009.08.27

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