单选题 Many countries have made it illegal to talk into a hand-held mobile phone while driving. But the latest research provides further confirmation that the danger lies less in what a motorist's hands do when he takes a call than in what the conversation does to his brain. Even using a "hands-free" device can impair a driver's attention to an alarming extent.
Melina Kunar of the University of Warwick and Todd Horowitz of the Harvard Medical School ran a series of experiments in which two groups of volunteers had to pay attention and respond to a series of moving tasks on a computer screen that were reckoned equivalent in difficulty to driving. One group was left undistracted while the other had to engage in a conversation about their hobbies using a speakerphone. As Dr. Kunar and Dr. Horowitz report in Psycbonomic Bulletin & Review, those who were making the equivalent of a hands-free call had an average reaction time 212 milliseconds slower than those who were not. That, they calculate, would add 5.7 meters to the braking distance of a car traveling at 100 kph. They found that the group using the hands-free kit made 83 percent more errors in their tasks than those who were not talking.
They also explored the effect of simply listening to something—such as a radio programme. For this they played a recording of the first chapter of Bram Stoker's "Dracula." Even though the test subjects were told to pay attention because they would be asked questions about the story afterwards, it had little effect on their reaction time. The research led by Frank Drews of the University of Utah suggests the same thing is true of the idle chatter of a passenger. Dr. Kunar reckons that having to think about responses during a phone conversation competes for the brain's resources in a way that listening to a monologue does not.
Punishing people for using hand-held gadgets while driving is difficult enough, even though they can be seen from outside the car. Stopping people making hands-free calls would probably be impossible—especially because more and more vehicles are now being fitted with the necessary equipment as standard. Persuading people to switch their phones off altogether when they get behind the wheel might be the only answer. Who knows, they might even come to enjoy not having to take calls. And they'll be more likely to arrive in one piece.

单选题 Which body part is most affected by talking into a cell phone when driving?
A. Hands. B. Feet. C. Eyes. D. The brain.

单选题 In Kunar and Horowitz's experiments, the subjects who performed tasks while talking ______.
A. reacted more quickly and made fewer mistakes
B. reacted more quickly, but made more mistakes
C. reacted more slowly, but made fewer mistakes
D. reacted more slowly and made more mistakes

单选题 According to Frank Drews, listening to a passenger talking ______.
A. affects drivers more than a phone conversation
B. affects drivers more than listening to a story
C. has less effect on the drivers than a phone conversation
D. has less effect on the drivers than listening to a story

单选题 The law forbidding the use of hand-held phones when driving ______.
A. is necessary and feasible
B. has been frequently broken
C. will arouse heated debate
D. has been widely observed

单选题 The best hope of stopping people using hands-free phones lies with ______.
A. the lawmakers B. car manufacturers
C. drivers themselves D. new technology

单选题 The purpose of the passage is to ______.
A. inform people of the danger of using phones while driving
B. call on lawmakers to make new road laws on the use of cell phones
C. offer suggestions for drivers who use cell phones while driving
D. weigh the benefits and harms of using phones when driving