Oil became a useful product only in the middle of the eighteen hundreds.

VOA: special.2010.02.25

If you agree with my estimates, then you should do this as an investor, you should hold only some mixture of this tangency portfolio, which is 9% oil, 27% stocks, and 64% bonds.

如果你赞同我的估计值，那么作为一个投资者的话你应该这么做，你应该只持有,符合这个切线投资组合比例的投资，即9%的石油，27%的股票，和64%的债券。

耶鲁公开课 - 金融市场课程节选

Oil is only six percent of its economy.

VOA: special.2009.12.04

The oil,as you can see,has depth. It's not only the size of Manhattan in area, but it is several hundred meters in depth."

VOA: standard.2010.05.17

The first trap shows no signs of oil, only mud stirred up by recent storms.

VOA: standard.2010.05.06

"So what this points out is that these types of oil disasters are not only posing risks to marine life and to fisheries and to the economy of coastal communities."

VOA: standard.2010.08.05

In December, Russian President Dmitri Medvedev criticized Rosneft, the state run company that owns the world's largest oil and gas reserves, for spending only of its revenues on research and development.

VOA: standard.2010.02.03