RECENT research shows that in China 44 percent of schoolboys and 19 percent of schoolgirls have tried smoking. Besides long-term health problems like heart disease and cancers, the nicotine (尼古丁) and other toxins (毒素) in cigarettes can quickly ruin a person’s skin, breath, and athletic performance. If you’ve started smoking, you will find it’s hard to stop because you’re addicted to nicotine. But the strategies below may help you quit: