精选优质文档-倾情为你奉上You should spend about 20 minutes on this task.The two graphs show the main sources of energy in the USA in the 1980s and the 1990s.Write a report for a university lecturer describing the changes which occurred.Write at least 150 words.model answer:The two graphs show that oil was the major energy source in the USA in both 1980 and 1990 and that coal, natural gas and hydroelectric power remained in much the same proportions. On the other hand, there was a dramatic