8 . Car companies such as Tesla and Nissan have been leading the way in electric car technology. What makes these car “green” is that because they run on electricity instead of gas, they do not give off any polluting greenhouse gases. The Toyota Mirai is also a kind of green car, since it is powered by a hydrogen fuel battery(氢燃料电池).

Hydrogen, as you know, exists in large quantities on the earth. It was used to power gaslights for centuries before electric lights came along. Hydrogen fuel can be made from many sources including water, natural gas and even rubbish. As for energy contained, 9.5kg of hydrogen is similar to 25kg of gas. According to Toyota, the two tanks on the Mirai hold 5kg of hydrogen, and can cover a distance of over 300 miles. This is twice the output of gas cars.

In a hydrogen fuel battery, the one proton (质子)and one electron in a hydrogen atom(原子) are broken up. While the electrons power the car, the hydrogen protons work with the oxygen atom to produce water. At the same time, it also produces a lot of heat which turns this water into water vapor. This is the reason why cars running on hydrogen fuel batteries give off water vapor from their exhaust pipes when running.

According to Toyota, it takes only 5 minutes to refill a hydrogen tank, which is much quicker than charging (充电) electric cars. However, the biggest difficulty for the company is the availability of hydrogen-charging stations. California and the New England states are in the process of building a hydrogen superhighway—with charging stations along the way. Countries like Germany, Japan and UK are also adding more charging stations.

The Toyota Mirai will be available in the U.S. in the second half of 2015 for $ 58,000. This hydrogen-fueled car will probably take the place of gas cars in the near future. After all, it is an energy-saving and environment-friendly car.

1. According to the text, nowadays hydrogen .

A．can only be used as a fuel for cars.

B．is a newly-discovered energy source

C．provides more energy than the same amount of gas

D．will soon become the main fuel for most of Toyota’s cars

2. The third paragraph is mainly about _________. .

A．water vapor and weather	B．how the Toyota Mirai works
C．different kinds of batteries	D．why hydrogen is very popular

3. What can we learn about the Toyota Mirai?

A．It runs on both gas and hydrogen.

B．It will soon take place of electric cars.

C．It gives off only a few polluting greenhouse gases.

D．It may sell well with more charging stations around.

4. The underlined word “availability” in Paragraph 4 can be replaced by________?

A．practicality	B．instruction
C．expansion	D．composition

9 . There’s a continuing controversy over whether electric vehicles should produce sounds to let the blind and other pedestrians know they’re on the scene. Some think those sounds should be standardized—like the “beep, beep, beep” of heavy machinery backing up, so you’ll think “something heavy is coming this way” when you hear it — and some think any sound will do.       

This is a serious subject. Plug-in hybrid cars (电混动力车) and battery electric vehicles are super-quiet, and a study at the University of California, Riverside concludes that people listening to recordings on headphones can hear a regular gas car coming from 28 feet away, but a hybrid in battery mode only when it’s 7 feet away.

In response, the European Union has put new rules into play: all new electric vehicle models must have a sound-producing device, which sounds like a traditional engine. Starting in 2021, all new electric vehicles of any model will need the Acoustic Vehicle Alerting System or AVAS. That sound will come into play when the car is traveling backwards or when it’s traveling at less than 12 miles an hour — speeds at which cars are more likely to be mixing with pedestrians.     

That’s a nice start, say representatives for the blind, but more is needed. “We’re calling on the government to take this announcement further by requiring AVAS on all existing electric and hybrid vehicles and ensuring drivers have them switched on,” John Welsman, guide dog owner and Guide Dogs staff member, said in a statement.

Drivers in most cases have the ability to shut off the device when needed. My guess is that they will eventually be standardized so your mind will automatically register “electric car” when you hear it. And that’s probably a good thing to reduce the mayhem (混乱) on the roads.

1. How does the author show “electric cars are quiet” in Paragraph 2?

A．By making a classification.

B．By making a comparison.

C．By analyzing cause and effect.

D．By setting down general rules.

2. What can be learned about the AVAS?

A．It was developed by the European Union.

B．It was designed for inexperienced drivers.

C．It consists of a sound-producing device and an engine.

D．It warns pedestrians of the coming of an electric car.

3. What does John Welsman think of the new rules?

A．They are too strict for drivers.

B．They are too complex to follow.

C．They need further improvement.

D．They hardly allow for any flexibility.

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

A．Electric cars with a standardized sound-producing device.

B．A new type of electric car on sale.

C．Problems with the electric cars.

D．Quiet electric cars.