11．Learning to drive is important to the independence of teenagers，but it is also a great responsibility．Although having a law that keeps 16-year-old drivers from having more than one teenager in the car with them seems unfair，there are convincing reasons for this requirement．
The Insurance Institute of Highway Safety reports that teens are four times more likely than older drivers to be involved in an automobile accident．It also reports that 16and 17-year-old drivers are twice as likely to have an accident if they have two teenage friends in the car and four times if they have three or more teenage friends in the car with them．Fatal crashes of 16-year-old drivers involve the highest percentage of speeding，driver error，and number of passengers．This information is enough to cause any reasonable person to wonder about the wisdom of allowing new teen drivers to take a carload of friends anywhere，even if the law permits it．
A study at the National Institutes of Health indicates that the part of the human brain that controls judgment and evaluates the consequences of our actions might not be fully formed until the age of 25．Until this study，researchers had placed the age of 18．If this is true，it could explain the reckless（魯莽的）behavior of many teens，behavior that even extends into their twenties．It could also be a strong reason for being watchful about the driving settings of young people．
This is not the only study that indicates such concern is necessary．One study at Temple University in Philadelphia examines the results of peer pressure in risky driving situations．The study，which uses a driving game，has an individual guide a car through a course，both alone and in the presence of friends．Three different age groups participated in the study：13-16，18-22，and 24and older．Members of the oldest group showed caution whether driving alone or with friends present，but the two younger groups took more chances when they were with their friends．Furthermore，because these drivers were accustomed to the noise an disturbance of many passengers，they were unable to see their own mistakes．Once again，this is a good suggestion that a law restricting the number of teenagers in the car with a young driver is a good idea．
12．What does the author mainly tell us in Paragraph 2？B
A．There are many causes behind the teen's driving accidents．
B．It's reasonable to strictly limit the passenger number of teen drivers．
C．New teen drivers have to ask permission before driving with friends．
D．Many deaths have occurred because of inexperience and overconfidence．
13．From the two studies，the author probably suggests thatD．
A．different age groups have different peer pressure
B．underdeveloped brain makes teens ignore their mistakes
C．teenagers often give wrong judgments above passengers'notice
D．driving settings are bound up with the risk of accidents
14．We can infer that the law restriction can probablyA．
A．protect teens on the highway
B．raise teens'driving skills
C．reduce the number of fatal crashes
D．force teens to drive with wisdom
15．What does"it"refer to in Paragraph 2？D
A．Number of passengers．
B．This information．
C．Wisdom．
D．Teen drivers take a carload of friends anywhere．
