阅读理解。 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. 1. The underlined word 'longevity' in the second paragraph probably refers to '_____'. [     ] A. health B. long life C. ageing D. effect 2. The text mainly talks about _____. [     ] A. men's heart cells B. women's ageing process C. the gender difference D. hearts and long life 3. According to the text, the UK scientists have known that _____. [     ] A. women have more cells than men when they are born B. women can replace the cells that enable the heart to beat C. the female heart loses few of the cells with age D. women never lose their pumping power with age 4. If you want to live longer, you should _____. [     ] A. enable your heart to beat much faster B. find out the reason for ageing C. exercise regularly to keep your heart healthy D. prevent your cells from being lost