There's another reason to clean those running shoes．Energetic exercise may help prevent vision（视力） loss，according to a pair of studies from the US Department of Energy's Lawrence Berkeley National Laboratory．The research offers hope for people trying to find ways of eye diseases．
"Besides getting eye exams，people can take a more active part in protecting their eyesight，"says Paul Williams，who carried out the research．"The studies suggest that people can perhaps reduce their danger of these diseases by taking part in a fitness treatment that includes enough exercise．"
Cataract（白内障） is the leading cause of blindness．More than one half of people in the US over the age of 65 suffer from some form of cataracts．
Diseases have several known reasons，such as sunlight exposure and diabetes（糖尿病） in the case of cataracts．Now，it appears that enough exercise may be one way to treat the disease．
To carry out the research，Williams examined information collected in the National Runners'Health Study，which he set up in 1991 to find out the health help of running．
In this case，he followed about 29，000 male runners and 12，000 female runners for more than seven years．Of these people，733 men reported being diagnosed（诊断） with cataracts filled out at the end of the study．Too few women reported cataracts to follow．
Men who ran more than 5.7 miles per day had a 35 percent lower risk of developing cataracts than men who ran less than 1.4 miles per day．The study also studied men's 10 kilometer race performances，which is a good sign of complete fitness．

(1) From the underlined sentence in Paragraph 1 we know we should ______ ．

A. keep our shoes clean every day

B. clean our shoes and put them in order

C. put on our shoes to do some energetic exercise

D. clean our shoes after we attend a race at school

(2) What can most probably cause blindness according to the passage？ ______

A. Cataracts．	B. Sunlight exposure．
C. Diabetes．	D. Nearsighted eyes．

(3) Which of the following is NOT true？ ______

A. Exercise may be one way to treat diabetes．

B. One half of Americans suffer from cataract．

C. Williams started the study in 1991．

D. There were 41，000 runners attending the study．

(4) What is the best title for this passage？ ______

A. Energetic Exercise Is of Great Help

B. Protect Your Eyes with Care

C. Prevent Your Eyesight Losing

D. Energetic Exercise May Help Prevent Eyesight Loss．