B
(2016·河北省唐山市统一考试)Hybrid cars (混合动力车) are cars that run on petrol and electricity. They have a small standard petrol engine and a battery
electric motor to provide electric power.
There are some differences between different models of hybrid cars, but the general principle is that the car runs on petrol, and the electric motor kicks in when additional power is required, for example, when going uphill or accelerating. In some hybrid cars the petrol engine turns itself off when not needed, for example when the car has stopped at traffic lights, keeping only the electric engine running.
Conventional cars have large engines to deal with driving uphill and accelerating. Hybrid cars have much smaller petrol engines, improved by electric motors when needed, so they use less petrol. Another way that fuel consumption is cut is by a system of “regenerative (再生的) braking”. The electric motor is used to slow down the car, rather than conventional brakes. The energy produced by slowing the car is changed into electrical power, which is automatically stored in the battery. In effect, the battery recharges when you brake. In conventional cars the energy produced when braking is wasted.
In 1928, Ferdinand Porsche built an experimental hybrid car. The first massproduced hybrid car, the Toyota Prius, came out in Japan at the end of 1997. However, hybrid cars became available in the USA only in 1999. As they use less fuel, hybrid cars are cheaper to run. There are also many voices in place to encourage people to buy them. In some countries, hybrid car owners pay a lower rate of tax, and don't have to pay on certain roads. In some cities, hybrid cars are allowed to park for free.
【2017届高考英语一轮复习夯实训练:Unit 21《Human Biology》(北师大版含解析)】相关文章:
★ 【浙江专用】2014届高考英语一轮复习课时作业(二)必修1Unit 2《English around the world》
★ 四川省2016届高考英语一轮复习课时作业(43) Module 1 Deep South 外研版选修8
★ 2014届高考英语一轮复习课时作业(十八)必修3Module 6《Old and New》(外研版)
★ 2017届江苏省淮安市新马中学高考牛津译林版英语一轮复习活动单:模块6 Unit 2《What is happiness to you》
★ 【课堂新坐标】2017届高考英语(通用版)二轮复习书面表达专题训练:技法6 规避重复适当进行句式升级(含解析)
★ 湖南省汝城二中2014届高考英语一轮复习阅读训练 (48)
★ 安徽省淮南市2014高考英语一轮单项选择及文章训练(5)及答案
★ 湖南省汝城二中2014届高考英语一轮复习阅读训练 (74)
★ 【北师大版】2014届高考英语一轮复习指导课时作业:Unit 9 B卷 Word版含解析
★ 【北师大版】2014届高考英语一轮复习指导课时作业:Unit 6 B卷 Word版含解析
最新
2017-04-24
2017-04-24
2017-04-24
2017-04-24
2017-04-21
2017-04-21