共用题干题

< p>Where do cars get their energy from？For most cars，the answer is petrol.< span style="text-decoration:underline;">21< /span> some cars use electricity.These cars have < span style="text-decoration:underline;">22< /span> motors that get their power from large batteries.< br/>In < span style="text-decoration:underline;">23< /span>，there are even cars that have < span style="text-decoration:underline;">24< /span> an electric motor and a petrol motor.These types of cars are < span style="text-decoration:underline;">25< /span> hybrid（混合）cars.< br/>Most people tend to think of electric cars as a new < span style="text-decoration:underline;">26< /span>，but they have been around for a long time.In the < span style="text-decoration:underline;">27< /span> 19th and early 20th centuries electric cars were common because the technology for petrol engines was not very advanced.< br/>But < span style="text-decoration:underline;">28< /span> the petrol engine became easier to make and more powerful，this type of engines became the most < span style="text-decoration:underline;">29< /span>.Interest in electric cars was high in the l970s and 1980s because < span style="text-decoration:underline;">30< /span> became very expensive.< br/>Recently，electric cars have again become well-liked because people want cars that pollute < span style="text-decoration:underline;">31< /span>.Electric cars are better than petrol cars < span style="text-decoration:underline;">32< /span> several ways.The biggest benefit is reduced pollution.< br/>In areas < span style="text-decoration:underline;">33< /span> there is a high percentage of electric cars，pollution is not that serious.The second benefit of electric cars is a < span style="text-decoration:underline;">34< /span> in the dependence on foreign oil.< br/>Several countries don’t want to < span style="text-decoration:underline;">35< /span> on oil from other countries.Since electric cars can run on electricity from coal or nuclear power stations，there is less need to import oil.< /p>

30处应填（）。