单选题 In the late morning of April 20th, 1999 a pair of teenagers, Dylan Klebold and Eric Harris, walked into the cafeteria at Columbine High School in Colorado and began gunning down their classmates. The two senior-year students killed 13 people in a 45-minute rampage before turning their weapons on themselves. The massacre remains the deadliest high-school shooting in American history.
In the days after the killings it emerged that, besides enjoying violent movies, the two liked playing "Doom", a bloody video game from the mid-1990s in which the heavily armed players use shotguns and rocket launchers to dispose of armies of zombies and demons. Parents, politicians and psychiatrists worried that exposure to virtual violence had prepared the ground for the real-world killings. Two years later the parents of some of the victims sued dozens of gaming companies, including id Software, the developers of "Doom", alleging that their products had contributed to the murders.
The massacre fed long-standing worries about video games, particularly in America, the industry"s biggest national market. The critics say there is a crucial difference between films, plays or books, where the players are just passive onlookers, and video games, where they are active participants in the simulated slayings. That, the argument goes, makes it more likely that they will resort to violence in the real world, too.
But the evidence is hard to pin down. Violent crime in America, Britain and Japan, the three biggest video-game markets, has dropped over the past decade at the same time as sales of video games have soared. That does not, by itself, exonerate the industry—after all, without games violent crime might have fallen still further. And several studies purport to show that playing violent video games raises aggression levels. But Chris Ferguson, a psychologist at Texas A&M International University, points out that much of this work is of poor quality. In a meta-analysis published in 2007, he found no evidence that games made their players violent. Indeed, after decades of research, he has concluded that violence in any media has little or no effect on their consumers.
Again, critics point to the interactive nature of video games, which allows their designers to tweak risks and rewards to make them irresistible. Some countries, including China and South Korea, are attempting to limit the number of hours that youngsters can play online games. Even games developers themselves have expressed concern about online games that rely on keeping players hooked. But there is no suggestion that games are addictive in the sense that they create physical dependence in their players. That makes them akin to other compelling but legal pastimes, such as gambling, following a football club or collecting stamps.
There is a long tradition of dreadful warnings about new forms of media, from translations of the Bible into dialects to cinema and rock music. But as time passes such novelties become uncontroversial, and eventually some of them are elevated into art forms. That mellowing process may already be under way as the average game-player gets older.

单选题 In critics" opinion, compared with films, games are more likely to induce violence in real life because ______.

单选题 The word "exonerate" is most closely in meaning to ______.

单选题 It can be inferred from Paragraph 5 that ______.

单选题 By mentioning cinema and rock music in the last paragraph, the author intends to illustrate that ______.

单选题 The purpose of this article is to ______.