The electronic cigarette（e-cigarette）industry is rapidly growing in the United States and the use of e-cigarettes is a public argument which continues because researchers do not yet know if e-cigarette use results in more benefit than harm. Now new research quantifies the balance of harm and benefit using the most current scientific evidence.

“Although the tobacco industry markets e-cigarettes as a tool to help adult smokers quit smoking, e-cigarette use actually only slightly boosts the adult smokers who are able to successfully quit,” says Samir Soneji, PhD, an associate professor at the Dartmouth Institute for Health Policy and Clinical Practice. “On the other hand, e-cigarettes may promote cigarette smoking starting and afford much harm to adolescents and young adults once they are introduced to nicotine.”

Soneji's team calculated the expected years of life gained or lost from the impact of e-cigarette use on smoking pause among current smokers, and transition to long-term cigarette smoking among never-smokers. “E-cigarettes could lead to more than 1.5 million years of life lost because their use could largely make more and more adolescents and young adults eventually become cigarette smokers,” says Soneji.

Effective national, state, and local efforts are needed to reduce e-cigarette use among youth and young adults unless e-cigarettes are to afford a net population-level benefit in the future. “E-cigarettes will likely cause more public health harm than public health benefit unless ways can be found to largely decrease the number of adolescents and young adults who smoke and increase the number of smokers who use e-cigarettes to successfully quit smoking,” says Soneji. “We also need to close the regulatory（监管的）gaps that make e-cigarettes appealing to adolescents and young adults by reducing the availability of kid-friendly flavors and issuing product standards that reduce the level of some harmful and unhealthy materials in e-juice.”

【小题1】What does the underlined word “boosts” in the second paragraph mean？

A．Affects.

B．Slows.

C．Increases.

D．Guides.

【小题2】How do e-cigarettes affect young adults？

A．By causing them to ignore the meaning of life.

B．By causing them to lose interest in study.

C．By causing them to get involved in smoking.

D．By causing them to live an unhealthy lifestyle.

【小题3】What did Soneji and his team base their research on？

A．The data of e-cigarettes on the Internet.

B．The amount of nicotine in e-cigarettes.

C．The time of smokers’ using e-cigarettes.

D．The effect of e-cigarettes on smokers’ life.

【小题4】What suggestion does Soneji make to reduce young smokers in the last paragraph？

A．Making e-cigarettes less accessible.

B．Making e-cigarettes taste worse.

C．Getting support from the government.

D．Changing the materials of making e-cigarettes.