1 . Smart phones have been blamed for everything from taking drivers' attention from driving to keeping people on the sofa scrolling（滚屏）videos. But the smart phone that seems to be everywhere could just easily increase physical activity if it pushes its owner's buttons in the right way.

New research shows that making social connections（人际关系）through activity-tracking apps gets people to move more. And another study on the "Pokemon Go" phenomenon shows that the smart phone games got players to take thousands more steps than usual. Together, the studies show the potential（潜在性）of smart phones to push a range of people to be more active.

People who linked with friends on the activity-tracking app increase their steps by 400 a day on average, compared with people who made no social connections, according to Tim Althoff and two other computer scientists at Stanford University. Such opinions show the possibilities of smart phones and games to help with one of the most stubborn public health problems-that even people who want to be active have trouble staying active.

An NBA videogame, for example, will give players extra powers in the game if they reach a step goal in real life. The app "Zomies, Run! " uses audio stories to push people to run more.

Still, there is room for growth: Only about 4% of all health apps use "gamification", such as point-scoring or competition, according to a study published in October in BMJ Open." Gamification is actually quite closely linked with behavior change techniques, " says Dr. Elizabeth Ann Edwards, the study's lead author.

1. What does the underlined part in Paragraph 1 probably mean?

A．Impress successfully.	B．List completely.
C．Direct professionally.	D．Function properly.

2. How does the author prove the benefits of smart phones?

A．By listing some research results.	B．By raising some potential questions.
C．By analyzing some health problems.	D．By explaining some social connections.

3. According to the text, who are more likely to exercise more?

A．People who play smart phone games.	B．People who watch videos on the sofa.
C．People who make no social connections.	D．People who have trouble staying active.

4. What is the purpose of the last paragraph?

A．To summarize the previous paragraphs.	B．To provide some advice for the readers.
C．To introduce a new topic for discussion.	D．To add more information about the topic.