A recent study, published in last week’s Journal of the American Medical Association, offers a picture of how risky it is to get a lift from a teenage driver. Indeed, a 16-year-old driver with three or more passengers is three times as likely to have a (47) accident as a teenager driving alone. By (48) , the risk of death for drivers between 30 and 59 decreases with each additional passenger. The authors also found that the death rates for teenage drivers increased (49) after 10 p.m., and especially after midnight. With (50) in the car, the driver was even more likely to die in a late-night accident. Robert Foss, a scientist at the University of North Carolina Highway Safety Research Center, says the higher death rates for teenage drivers have less to do with "really stupid behavior" than with just a lack of driving (51) . "The basic issue" he says, "is that adults who are responsible for issuing licenses fail to (52) how complex and skilled a task driving is." Both he and the author of the study believe that the way to mitigate (使......缓解) the problem is to have states institute se-called graduated licensing systems in which getting a license is a multistage process. A graduated license requires that a teenager first prove himself (53) of driving in the presence of an adult, followed by a period of driving with night of passenger (54) before graduating to full driving privileges. Graduated licensing systems have reduced teenage driver crashes according to recent studies. About half of the states now have some sort of graduated (55) system in place, but only 10 of these states have restrictions on passengers. California is the strictest, with a novice(新手)driver prohibited from (56) any passengers under 20 (without the presence of an adult ever 25) for the first six months. A passengers B contact C experience D recognize E capable F restrictions G carrying H dramatically I contrast J accompany K acquaintance L inevitably M identify N fatal O licensing