A recentstudy,published in last week's Journal of American Medical Association,offers apicture of how risky it is to get a lift from a teenage driver. Indeed,a16-year-old

driver with three ormore passengers is three times as likely to have a fatal accident as a teenagerdriving alone,by contrast,the risk of death for drivers between 30 and 59

decreases with. eachadditional passenger.

The author alsofound that the death rates for teenage drivers increased dramatically after 10pm,and especially after midnight.With passengers in the car,the driver was even

more likely to diein a late-night accident.

Robert Foss,ascientist at the University of North Carolina Highway safety Research Center,says the higher death rates for teenage drivers,have less to dowith"really stupid

behavior" thanwith just a lack of driving experience."The basic issue,"hesays,"is that adults who are responsible for issuing licenses fail torecognize how complex and

skilled a taskdriving is."

Both he and theauthor of the study believe that the way to mitigate（使······缓解）the problem is to havestates institute so-called graduated licensing systems,in which

getting a license isa multistage process.A graduated license requires that a teenager first provehimself capable of driving in the presence of an adult,followed by a period of

driving withpassenger restrictions,before graduating to full driving privileges.

Graduate licensingsystems have reduced teenage driver crashes,according to recent studies. Abouthalf of the states now have some sort of graduated licensing system in

place,but only 10 ofthose states have restrictions on passengers. California is the strictest,witha novice（新手）driverprohibited from carrying any passenger under 20

(without thepresence of an adult over 25)for the first six months.A graduatedlicense is issued to a driver who________.

A.is at least amiddle school graduate

B.has learneddriving at a driving school

C.gains full drivingrights step by step

D.has a drivingexperience long enough