题目内容：

    There’s something satisfying about volunteering. Studies have shown that volunteering helps people who donate their time feel more socially connected, thus warding off loneliness and depression. But a growing body of evidence suggests that people who give their time to others might also be rewarded with better physical health, including lower blood pressure and a longer lifespan.

Evidence of volunteerism’s physical effects can be found in a recent study from Carnegie Mellon University, published this month in Psychology and Aging. Adults over age 50 who volunteered on a regular basis were less likely to develop high blood pressure than non-volunteers. High blood pressure is an important indicator of health because it contributes to heart disease, stroke, and premature death.

It’s impossible for this study to prove that volunteering was directly responsible for the lower blood pressure. People who volunteer may be more likely to do other things, like eating a healthy diet or exercise, which lower blood pressure. But the results are in line with other findings on the topic.

How might volunteering contribute to lower blood pressure？Performing volunteer work could increase physical activity among people who aren’t otherwise very active, says leading study author Rodlescia Sneed, a doctoral candidate in social and health psychology at Carnegie Mellon University. It may also reduce stress. “Many people find volunteer work helpful with respect to stress reduction, and we know that stress is very strongly linked to health out-comes,” she says.

A 2012 study in the journal Health Psychology found that participants who volunteered with some regularity lived longer, but only if their intentions were truly altruistic. In other words, they had to be volunteering to help others-not to make themselves feel better.

The Greek philosopher Aristotle once guessed that the essence of life is “To serve others and do good.” If recent research is any indication, serving others might also be the essence of good health.

1.Which can replace the underlined phrase “warding off” in paragraph 1？

A.getting rid of. B.keeping up with.

C.running out of. D.putting up with.

2.Why does the author mention the study from Carnegie Mellon University？

A.To prove the benefit of volunteering to health.

B.To find out volunteerism’s physical effects on heart.

C.To explain the connection between exercise and health.

D.To warn readers the danger of volunteering to blood pressure.

3.What can we learn from what Rodlescia Sneed said？

A.Volunteers are supposed to be more outgoing.

B.Volunteer work can make people lack sports.

C.Taking appropriate exercise can strengthen social connection.

D.Performing volunteer work contributes to reducing stress.

4.What’s the text mainly about？

A.Volunteering can lower blood pressure.

B.Volunteering is beneficial to mental health.

C.Volunteering may be good for body and mind.

D.Volunteering can avoid suffering from heart disease.