Where do cars get their energy from? For most cars, the answer is petrol.　21　some cars use electricity. These cars have　22　motors that get their power from large batteries. In　23　,there are even cars that have　24　an electric motor and a petrol motor. These types of cars are　25　hybrid（混合）cars.
　　Most people tend to think of electric cars as a new　26　,but they have been around for a long time. In the　27　19th and early 20th centuries electric cars were common because the technology for petrol engines was not very advanced．But　28　the petrol engine became easier to make and more powerful, this type of engines became the most　29　. Interest in electric cars was high in the 1970s and 1980s because　30　became very expensive. Recently, electric cars have again become well-liked because people want cars that pollute　31　.
　　Electric cars are better than petrol cars　32　several ways. The biggest benefit is reduced pollution. In areas　33　there is a high percentage of electric cars, pollution is not that serious. The second benefit of electric cars is a　34　in the dependence on foreign oil. Several countries don"t want to　35　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.

A. popular

B. comfortable

C. difficult

D. dangerous