题目内容：

    By now it's almost common knowledge that spending time in nature is good for you. Areas with more trees tend to be less polluted, so spending time there allows you to breathe easier. Spending time outdoors has been linked with reduced blood pressure and stress and seems to motivate people to exercise more.

“So it'll come as surprise that there's research showing that spending time in nature is good. There are dozens of papers showing that,” University of Exeter Medical School researcher Mathew P.White said.“We get this idea-patients are coning to us and they are asking, ‘Doctor, how long should I spend? ’And the doctor is saying,‘I don't really know.’”

So White and his team decided to find out by using data collected from nearly 20,000 people in England through the Monitor of Engagement with the Natural Environment Survey. And their answer? Two hours a week. People who spent at least that much time in nature either all at once or totaled over several shorter visits were more likely to report good heath and psychological well-being than those with no nature exposure.

Remarkably, the two-hour standard applied to men and women, to older and younger folks, to people from different ethnic backgrounds, occupational groups, socioeconomic levels, and so on. Even people with long-term illnesses or disabilities benefited from time spent in nature- as long as it was at least 120 minutes per week.

While the findings are based on a vast number of people, White cautions that it's rally just a correlation. Nobody knows why of how nature has this benefit, or even if the findings will stand up to more strict investigation.

“I want to be rally clear about this. This is in very early stages.We're not saying everybody has to do 120. This is really to start the conversation, saying, what would a threshold look like? What research do we need to take this to the next step before doctors can have the true confidence to work with their patients? But it's certainly a starting point.”

1.What does White want to figure out in the survey?

A.The benefits of being outside.

B.How long we should stay in nature.

C.The significance of outdoor activities.

D.Whether the British spend enough time in nature

2.What can we learn from the last two paragraphs?

A.The two-hour standard applies to everyone.

B.The reason why nature is beneficial is clear.

C.Further study is needed to confirm White's result.

D.The findings of White's survey have bee widely used.

3.What does underlined word“threshold”in the last paragraph mean?

A.Strict investigation. B.Following step.

C.Healthy lifestyle. D.Staring point.

4.What can be the best title for this text?

A.Nature and Health B.Two-hour Staying in Nature

C.Tips to Improve Health D.The Starting Point