More teen-agers smoke today than at any time since the 19 15 s, a federal study shows. Overall, 35% of children 1 grades 9-12 smoke cigarettes, a greater 2 than the 25% of adults who smoke. 3 it is illegal to buy cigarettes until age 18, more than 20 % of kids who 4 them in stores are not asked for proof of 5 , and they get cigarettes just as adults do: They walk in and buy them, 6 no one checks their age. At a high school, 7 inaugurated ( 发起 ) a smoke-free campus this year, students who sneak cigarettes between classes 8 that stricter laws will cut 9 .Sixth-and seventh-graders 10 at a middle school say they have little trouble 11 stores to sell them cigarettes, 12 unsupervised vending machines ( 自动售货机 ) or getting 13 students to buy cigarettes for them. They say they have 14 the most successful store-buying line early: “ My 15 is waiting in the car.” 16 smoking becomes less popular in adults, smoking becomes a form of rebellion. Too often the rebellion leads to the tragic consequences of a 17 smoking habit. Health experts warn that 18 teen smokers quit soon, advances made in reducing lung cancer and heart disease in the past 20 years will be 19 . This will have a dramatic effect on the nation’s 20 .