Worldwide every day,we devour the energy equivalent of about 200 million barrels of oil.Most of the energy on Earth comes from the Sun.In fact enough energy from the Sun hits the planets surface each minute to cover our needs for an entire year,we just need to find an efficient way to use it.So far the energy in oil has been cheaper and easier to get at.But as supplies dwindle,this will change,and we will need to cure our addiction to oil. Today petroleum,a mineral oil obtained from below the surface of the Earth and used to produce petrol,diesel oil and various other chemical substances,provides around 40% of the worlds energy needs,mostly fuelling automobiles.The US consumes n quarter of all oil,and generates a similar proportion of greenhouse gas emissions. Most experts predict we will exhaust easily accessible reserves within 50 years,though opinions and estimates vary.We could fast reach an energy crisis in the next few decades,when demand exceeds supply.As conventional reserves become more difficult to access,others such as oil shales and tar sands may be used instead.Petrol could also be obtained from coal.
小升初模拟题及答案
2015小升初英语模拟试卷及答案(四)
2015小升初英语模拟试卷及答案(七)
小升初模拟题及答案
小升初英语练习题及答案解析(四):完成句子、阅读理解
小升初英语冲刺模拟试题及答案(一)
小升初英语强化试题及答案解析(七)
小升初英语冲刺模拟题及答案汇总
2015小升初英语模拟试卷及答案(五)
小升初英语强化试题及答案解析(五)
2015小升初英语模拟试卷及答案(三)
小升初英语练习题及答案解析(十一):单项选择、补全对话
小升初英语冲刺模拟试题及答案(二)
小升初英语强化试题及答案解析(八)
小升初模拟题及答案
小升初英语冲刺模拟试题及答案(九)
小升初英语强化试题及答案解析(三)
小升初英语练习题及答案解析(十三):单项选择、阅读理解
小升初英语强化试题及答案解析(二)
小升初英语练习题及答案解析(十二):单项选择、单词拼写
小升初英语冲刺模拟试题及答案(四)
小升初英语模拟题及答案
小升初英语练习题及答案解析(五):单项填空、完型填空
2015小升初英语模拟试卷及答案(二)
小升初英语练习题及答案解析(八):完成句子、阅读理解
小升初英语强化试题及答案解析(一)
小升初英语冲刺模拟试题及答案(十)
小升初模拟题及答案
小升初模拟题
小升初英语练习题及答案解析(九):单项选择、阅读理解
| 不限 |
| 英语教案 |
| 英语课件 |
| 英语试题 |
| 不限 |
| 不限 |
| 上册 |
| 下册 |
| 不限 |