A、The dramatic increase in demand for oil. B、The dramatic increase in oil prices. C、The political tension between Arab countries

　　The US made its first export of crude oil in four decades last Thursday. The exports were banned in the mid-1970s. That ban was lifted a few weeks ago.
　　(5)The Arab Oil Embargo began in 1973. Arab nations who produce oil dramatically limited their shipments to the US. This was done to punish the US over its military support for Israel. (6)The Arab cartel later expanded the embargo to other countries, and oil prices soared worldwide. The embargo had many short- and long-term effects on global politics and the global economy. The skyrocketing prices led to a drop in demand for oil. Countries looked for alternative energy sources such as natural gas, nuclear energy and coal. Oil-producing nations outside the Middle East increased their production and relied more on domestic supply.
　　Every president since Nixon has made energy security a top priority, but each president has dealt with the problem in different ways. (7)President Barack Obama has looked for energy sources apart from imported oil, such as natural gas from wells in the US.
　　5. What can we learn about the Arab Oil Embargo?
　　6. What impact did the embargo bring?
　　7. How does President Obama deal with energy security?