题目内容：

    New research has found that young adults who smoke both tobacco cigarettes and e-cigarettes appear to have a higher risk of stroke than those who only smoke tobacco.

Carried out by researchers at George Mason University, the new study looked at 161,529 participants aged 18 to 44 years of age, who were surveyed about their cigarette and e-cigarette use.

The researchers also calculated the participants’ risk of experiencing a stroke, taking into account factors such as how much participants smoked, high blood pressure, diabetes, cholesterol levels, body mass index and physical activity levels.

The findings, published in the American Journal of Preventive Medicine, showed that the participants who smoked cigarettes and used e-cigarettes were nearly two times more likely to have a stroke compared to current cigarette — only smokers, and nearly three times more likely than non-smokers.

The team also found that participants who used only e-cigarettes had a lower risk of stroke than those who smoked only tobacco cigarettes. In fact, those who used e-cigarettes on their own did not have a significantly greater risk of stroke than non-smokers.

However, the researchers failed to find any clear benefit from switching from cigarette smoking to using e-cigarettes, even though many people believe that e-cigarettes are a “healthy” alternative to cigarettes, and a way to help smokers kick the habit. They also noted that the nicotine dependence and toxicity associated with e-cigarettes is worrying, particularly among young adults who smoke them for fun and the range of flavors.

“It’s long been known that smoking cigarettes is among the most significant risk factors for stroke. Our study shows that young smokers who also use e-cigarettes put themselves at an even greater risk,” explained lead investigator Tarang Parekh, MBBS, MSc. “This is an important message for young smokers who perceive e-cigarettes as less harmful ones and consider them a safer alternative.We have begun understanding the health impact of e-cigarettes and concomitant cigarette smoking, and it’s not good.”

“Our findings demonstrate an additive harmful effect of e-cigarettes on smokers’ blood vessels, hearts and brains,” explained Parekh.

“Consider this study as a wake-up call for young vapers, clinicians, and healthcare policymakers. There is an urgency to regulate such products to avoid economic and population heath consequences and a critical need to conduct further research on the benefits and risks of smoking cessation altermatives,” warned Parekh.

1.What does the text belong to?

A.A science fiction. B.A news report.

C.A short story. D.A public announcement.

2.What can we know about the participants?

A.A few elderly people were surveyed.

B.Some of them are non smokers .

C.All of them use cigarettes and e-cigarettes.

D.They have a lower risk of stroke than others .

3.What does the underlined word “perceive” in Paragraph 7 mean?

A.Think. B.Practise.

C.Predict. D.Receive.

4.What did the the new research find?

A.Smoking cigarettes is among the most significant risk factors for stroke.

B.E-cigarettes are a “healthy” alternative to cigarettes.

C.Smoking both tobacco and e-cigarettes can make young adults at an greater risk of stroke.

D.It is beneficial to switch from cigarette smoking to using e-cigarettes.