题目内容：

    Young American adults own smartphones at a higher rate than any other age group.

Researchers from Duke University wanted to see if using the smartphone with a low-cost weight-loss App might help young adults in the US who are overweight. If you're rooting for smartphones to solve all our health problems,you're not going to like what the researchers found.The smartphone App doesn't help young adults lose any weight

The study looked at 365 young adults aged 18 to 35.A third of the young adults used an Android App created for the study,which not only tracked their calories,weight and exercise but also offered interactive features like goal setting.games and social support.Another third of the young adults received six weekly personal coaching courses,followed by monthly phone follow-ups.Plus,this personal coaching group was also encouraged to track thcir weight, calories and exercise by smartphones.The last third of young adults were put into a control group and given three necessities on healthy eating and exercise-nothing else.

Researchers tracked the young adults progress after six months,one year and two years. The personal coaching group lost more weight than the other two groups at the six-month mark, but that lead(领先)disappeared at the one-and two-year follow-up.As for the group using the smartphone App,their average weight loss was never more than the other two groups. Lead author Laura Svetkey says that she and her colleagues were both surprised and disappointed at the results.“Given the power of cell phone apps and the popularity of these health and fitness apps,we thought this might be good to provide an effective solution at a low cost,”says Svetkey.

But Svetkey says it's difficult to get the same level of intensity(强度)in an App that you might get through personal coaching,Plus,she says,people tend to stop using weight-loss apps after a while.

There are good reasons to help young adults control their weight.Weight gain during the young adult years is associated with a variety of health problems later in life,including metabolic syndrome and cardiovascular disease.

Since I am a young American adult who uses a popular weight-loss App on my iPhone,I wonder if there is any real harm in using one of these apps,even if they aren't proven effective in research studies.So I turn to Svetkey.She says,"These study results aren't the reason to give up hope about the potential for weight-loss apps,but instead are the reason to strengthen research efforts.More work is needed to understand how to use the technology and show its strengths in a way that will lead people to change their eating and exercise behaviors.”

1.The underlined part"rooting for”in Paragraph 2 is closest in meaning to“".

A.disliking B.supporting

C.quitting D.doubting

2.From the passage we know that in the study

A.the group using the smartphone App lost the most weight

B.participants in the control group failed to lose weight

C.all participants surveyed gains weight two years later

D.the personal coaching group was more successful at the six-month mark

3.Which of the following does Laura Svetkey agree with?

A.Weight-loss apps in smartphones are an effective solution to over-weight people.

B.Compared with weight-loss apps,personal coaching is more effective.

C.Being overweight will cause serious diseases to people.

D.People should have confidence in weight-loss apps all the time.

4.From the last paragraph,we can infer that

A.there is a long way to go to help people lose weight with technology

B.people should eat less and exercise more

C.people are advised to give up using weight-loss apps

D.the more advanced technology is,the more benefits people will get