题目内容：

A recent university study found that current electric cars could be used for 87% of daily car journeys in the US. That figure could rise to 98% by 2020.

One hurdle to the widespread adoption of electric cars has been “range anxiety” ---drivers’ concerns about running out of petrol on a journey. While petrol stations are conveniently located across national road systems, the necessary network of electric charging stations is still being developed. In fact, charging points are becoming increasingly common throughout the USA.

Attitudes towards electric vehicles have changed quite considerably over the last few years. Not that long ago, electric cars met with doubt, and their high price drove customers away. Thanks to improvements in battery capacity(电池容量), recharging times, performance and price, the current generation of electric cars is starting to persuade critics.

As well as progress on the road, electric vehicles are taking to the sea and sky. Electric boats are among the oldest electric vehicles, having enjoyed several decades of popularity from the late 19th to the early 20th century before petrol-powered outboard motors took over. Now, the global drive for renewable energy sources is bringing electric boats back. Steps towards electric planes are also being made, with Airbus and NASA among the organizations developing and testing battery-powered planes. The experiments could soon make electric flight a reality.

Electric vehicles do not produce any emissions(排放物). Were the US to act on the study’s findings and replace 87 percent of its cars with electric vehicles, it would reduce the national demand for petrol by 61 per cent. However, because of the production processes and the generation of electricity required to charge these vehicles, they cannot claim to be completely emission-free. Even so, as many countries continue to increase their use of renewable energy sources, electric vehicles will become even cleaner.

1.The underlined word “hurdle” refers to ________.

A. limit    B. step

C. result    D. aim

2.Why were not the electric cars popular with many people in the past?

A. They were not widely improved.

B. They were very poorly made.

C. They were not good value.

D. They couldn’t travel at a high speed.

3.What is the purpose of Paragraph 4?

A. To show why more people have interest in electric cars.

B. To describe different ways electric vehicles can be used.

C. To introduce the history of electric vehicles

D. To explain why the world needs more electric cars.

4.Which of the following can be the best title for this passage?

A. Driving into the Future    B. Problems with Petrol Cars

C. My Dream Car    D. History of Electric Cars