It's one of the greatest medical mysteries. Why does a person who never smokes a single cigarette end up with lung cancer while another person who smokes for decades remains cancer-free? The answer may be buried deep inside our genetic formation. Three separate teams of researchers found a genetic change that increases the risk of lung cancer. One team of researchers found that if you have the changed genes and smoke, you are also more likely to smoke more cigarettes a day than a smoker without those varied genes. Is this a gene that makes you smoke? This gene doesn't make you more likely to begin to smoke, but if you smoke, you smoke more. The authors of the study disagree on whether the increased risk of lung cancer is because those people with the changed gene may smoke more or if it's the genetic change itself that leads to cancer. This study is so important because we are going to be able to understand those genetic differences. And in the future then, we can do a better job of preventing those from starting to smoke and helping those who started to smoke to quit. Further studies of the changed genes could explain more mysteries like why some people's attempt to kick the habit always ends up smoking.1. [听力文本资源] What have the researchers discovered? [听力文本资源]A) Genetic change leads to lung cancer.B) Genetic change decreases the risk of lung cancer.C) Genetic change often makes one begin to smoke.D) Genetic change is likely to make a smoker smoke more. 2. [听力文本资源] According to the passage, what does lung cancer have to do with? [听力文本资源]A) Living habits.B) Infectious virus.C) Genetic formation. D) Cigarette dependence.3. [听力文本资源] What is the speaker's attitude toward the future of this study? [听力文本资源]A) Indifferent.B) Negative.C) Neutral.D) Positive.