题目内容：

阅读小面短文，在空白处填入1个适当的档次或括号内单词的正确形式。

By now it’s almost common knowledge that spending time in nature is good for you. Areas with 1.(many) trees tend to be less polluted, so spending time there allows you to breathe easier. Spending time outdoors contributes to good health, with blood pressure and stress 2.(reduce), and seems to motivate people 3.(exercise) more.

A survey showed that people 4.spend 2 hours in nature — either all at once or totaled over several shorter 5.(visit) — were more likely to report good health and psychological well-being than those with no nature 6.(expose). Remarkably, the researchers found that less than two hours offered no significant benefits. The two-hour benchmark (临界值) 7.(apply) to men and women, to older and younger folks and so on. Even people8.long-term illnesses or disabilities benefited from time 9.(spend) in nature — as long as it was at least 120 minutes per week.

While the findings are based on 10.tremendous number of people, scientists caution that it’s really just a correlation. Nobody knows why or how nature has this benefit or even if the findings will stand up to stricter investigation.