please，method，when，expensive，popular，work，cause，either，down，journey

Electric cars may seem like a recent invention，but they've been around for years.In the early 1900s，there were more electric cars on the road than there were petrol （汽油） cars.At that time，petrol was（1）

expensive

expensive

compared with other fuels（燃料）.（2）

When

When

petrol prices dropped and new technologies were developed，electric cars went out of fashion.Instead，petrol cars became more（3）

popular

popular

because they could travel longer distances without stopping.
    During the 20th century，petrol cars got bigger，heavier，and faster.They needed more fuel，and it（4）

caused

caused

more air pollution.For years，car makers didn't worry about pollution.They didn't worry about the amount of petrol cars used，（5）

either

either

.But when people began to realise that there was not enough oil on the earth，they asked car makers to produce more efficient（高效能的）and less polluting cars.
    One（6）

method

method

of solving the problem was a "hybrid" car（混合動(dòng)力車），one that ran partly on petrol and partly on electricity.Hybrid cars became popular in the 2000s when petrol prices went up and the prices of hybrid cars went（7）

down

down

.
    An all-electric car uses no petrol.The problem，however，is that car batteries need to be recharged （再充電）.That makes electric cars not so useful for long（8）

journeys

journeys

.
    Many people are not（9）

pleased

pleased

with it.The government and car makers are（10）

working

working

together to develop safe，cheap，and useful electric cars.When people have these cars in the future，a petrol station may be a thing of the past.