VOA慢速英语:Scientists Study to Remove Carbon from the Atmosphere

短语讲解：

1.It was brought to the surface by the forces of plate tectonics millions of years ago.

millions of 成千上万的…，无数的…
例句：He helped energize and mobilize millions of people around the nation
他帮助激励和动员了全国数百万人。

2.They want to find out how the rocks managed to capture so much carbon over time.

find out 发现; 使发作; 使受惩罚
例句：You can find out whether they are prepared to share the cost of the flowers with you
你可以弄清楚他们是否愿意和你一起分担买花的费用。