64. We can know from the passage that

   A. the reason why ageing takes a greater loss on the male heart has been found out

   B. scientists are on the way to finding out why the male heart loses more of the cells

   C. the team has done something to prevent the male from suffering the greater loss

   D. women over 70 could lose more heart cells than those at the age of 20

C

   Unless we spend money to spot and prevent asteroids(小行星)now, one might crash into Earth and destroy life as we know it, say some scientists.

   Asteroids are bigger versions of the meteoroids(流星)that race across the night sky. Most orbit the sun far from Earth and don't threaten us. But there are also thousands of asteroids whose orbits put them on a collision(碰撞)course with Earth.

   Buy $50 million worth of new telescopes right now. Then spend $10 million a year for the next 25 years to locate most the space rocks. By the time we spot a destructive one, the scientists say, we'll have a way to change its course.

   Some scientists favour pushing asteroids off course with nuclear weapons. But the cost wouldn't be cheap.

   Is it worth it? Two things experts consider when judging any risk are: (1) How likely the event is; and (2) How bad the results if the event occurs. Experts think an asteroid big enough to destroy lots of life might strike Earth once every 500,000 years. Sounds pretty rare--but if one did fall, it would be the end of the world. "If we don't take care of these asteroids, they'll take care of us.”Says one scientist, "It's that simple.”

   The cure, though, might be worse than the disease. Do we really want fleets of nuclear weapons sitting around on Earth?”The world has less to fear from the terrible rocks than from a great nuclear fleet set against it,” said a New York Times article.

59. When reporting the news, the author seemed to be a little ______.

   A. angry      B. surprised     C. shocked     D. worried

B

   Why do men die earlier than women? The latest research makes it known that the reason could be that men's hearts go into rapid decline when they reach middle age.

   The largest study of the effects of ageing on the heart has found that women's longevity may be linked to the fact that their hearts do not lose their pumping power with age.

   "We have found that the power of the male heart falls by 20--25 percent between 18 and 70 years of age,”said the head of the study, David Goldspink of Liverpool John Moores University in the UK.

   "Within the heart there are millions of cells that enable it to beat. Between the age of 20 and 70,one-third of those cells die and are not replaced in men,”said Goldspink. "This is part of the ageing process."

   What surprises scientists is that the female heart sees very little loss of these cells. A

healthy 70-year-old woman's heart could perform almost as well as a 20-year-old one's.

  "This gender difference might just explain why women live longer than men,”said Goldspink.

   They studied more than 250 healthy men and women between the ages of 18 and 80,focusing on healthy persons to remove the confusing influence of disease.

   The team has yet to find why ageing takes a greater loss on the male heart, said Goldspink.

   The good news is that men can improve the health of their heart with regular exercise. Goldspink stressed that women also need regular exercise to prevent their leg muscles becoming smaller and weaker as they age.

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