题目内容：

The number of accidents involving pedestrians (行人) wearing headphones is on the rise , a report suggests, causing fresh warning from road safety groups in Britain .

A US-based study found a total of 116 reports of death or injury to pedestrians wearing headphones between 2004 and 2011 , jumping from 16 in 2005 to 47 in 2011 .

Most victims were men (68%) and under the age of 30 (67%) , with around one in ten of all cases (9%) under the age of 18 .Some 89% of the cases occurred in urban areas and more than half (55%) of the victims were struck by trains .

Eighty-one of the 116 accidents (70%) resulted in the person’s death--- even though a warning was sounded in around a third of the cases .

The study concluded , “ The use of headphone may be a safety risk to pedestrians , especially in environments with moving vehicles（cars） . Further research is needed to determine if and how headphone use threatens pedestrian safety .” British road safety groups warned pedestrians to be careful.

Floor Lieshout , director of Youth For Road Safety , said, “ This study shows once more the importance of using all of our senses while we are near traffic . It is important that we find an attractive way to make youth learn about the risks of wearing headphones in traffic .”

Andrew Howard , who is the head of road safety at the Automobile Association , added that some pedestrians can be “so focused in their own little world they forget the world going on around them”.That can include headphone wearers , Howard said, but also people talking on phones.

However , Howard said that more researches needed to be done.

Earlier studies have shown that people wearing headphones or talking on phones can suffer “inattentional blindness” which makes them isolated (孤立) from the world around them .

Ian Harvey , at the charity Civic Voice , said that “ to defeat isolation and to help build a civic(文明的) society , people need to interact(交往) with each other .

He said , “ A basis for any civilized society is communication--- Surfing the web , listening to MP3s , reading blogs or sending e-mail is not interacting with a person; it’s interacting with a machine.

“If people feel socially isolated , they need to have more face-to-face interactions with other human beings and in time , will begin to feel happier and more connected to the world and place they live in .”

1.What does the text mainly discuss ?

A. Recent research on the risks to pedestrians

B. Safety problems caused by wearing headphones.

C. The advantages and disadvantages of headphones

D. Traffic accidents in the United States

2.We can learn from the Us-bases study that _________ .

A. most victims died in the accidents

B. most accidents were caused by cars

C. most accidents happened in the countryside

D. most victims are under eighteen

3.Howard will probably agree that ____________ .

A. it is safe if you wear headphones in a proper way

B. people wearing headphones are more likely to go blind

C. most people wear headphones because of loneliness

D. it is dangerous to talk on phones while walking

4.What Lan Harvey said shows the importance of ___________ .

A. beating isolation                 B. communication between people

C. building a civilized society         D. new technologies