问答题 Public health experts are debating whether e-cigarettes (电子香烟) can help stop tobacco smoking. Research around this topic is sparse, but one new, relatively small study raises questions about whether e-cigarettes can rid tobacco smoker of their deadly habit. The study looked at 949 tobacco smokers—88 of whom also used e-cigarettes—and found that smoking e-cigarettes did not help them quit or reduce their use of cigarettes over the course of a year. E-cigarettes, which do not contain tobacco and give off no tar (焦油) or carbon monoxide (一氧化碳), are believed to be safer than regular tobacco cigarettes, and some argue that pushing people toward less dangerous nicotine-intake systems is better for them. But cutting down or quitting smoking altogether is the ultimate goal, and the new study suggests that's not happening.