可汗学院SAT语法练习：Petroleum Engineering: A Booming Career
The United States is currently experiencing an unprecedented energy boom. Much of the upswing in American energy production ① is due to the reason of the exploration of oil and natural gas in formations made up of shale rock. Previously, these deposits had been unobtainable, but as a result of technological developments such as horizontal drilling and hydraulic fracturing, these previously untapped reserves are contributing to a massive upswing in the production of domestic oil and gas. One study by the Energy Information Administration predicts that by 2016, the United States will be pumping tea million barrels of oil a day, ② an amount that would equal the oil output gf Saudi Arabia, the long-time world leader in the production of oil.
The sharp growth in energy production has had many social and economic impacts. One of these ③ affect is job growth. Petroleum engineers in particular have become some of the most sought after employees in the energy industry. Over the next decade, the job growth rate for petroleum engineers ④ are projected to be 26 percent, which is twice the average rate for all occupations in the United States. From 2009 to 2012, the number of jobs in the field of petroleum engineering ⑤plummeted from over 35,000 to 15,000.
The intense demand for petroleum engineers is due to the specialized nature of their work. When working in shale formations, petroleum engineers design and develop the methods for extracting oil and gas. In the Bakken ⑥ formation, a highly productive oil field located in North Dakota only 3.5 percent of the oil deposits in the rock are currently recovered. If a petroleum engineer is able to contribute to an increase in this rate of just a fraction of a percentage, it can mean millions of additional barrels
⑦ however, the demand for the expertise of a petroleum engineer is understandable. Further, a petroleum⑧engineers skills’ are applicable to areas beyond oil exploration. Petroleum engineers also commonly work in pollution cleanup, underground waste disposal, and water resource management.  One must gain admittance into an engineering program, preferably in petroleum engineering, and then complete a rigorous course of study in mathematics, physics, geology, chemistry, and the principles of engineering analysis.  While some petroleum engineers primarily work in labs or ⑨offices, many have to spend long hours at well sites, which are often located in remote areas around the country.  These job prospects are indeed promising, but becoming a petroleum engineer is not easy
 Though the career is ⑩challenging, petroleum engineers work exciting jobs at the heart of the dynamic energy industry. ⑪