.

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.

60. The underlined word "longevity" in the second paragraph probably refers to ____.

A. health    B. long life      C. ageing      D. effect

61. The text mainly talks about ______.

A. men's heart cells                 B. women's ageing process

C. the gender difference             D. hearts and long life

62. 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 health

D.prevent your cells from being lost

63. 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

.

       Thirty years ago, when the movie version of my novel Jaw was published, few people including me knew very much about great white sharks.For hundreds of generations, we humans have been taught to fear and hate sharks, and the movie touched a nerve of horror.

       Now something long thought impossible has happened.A great white shark was successfully held in capacity for several months.In August last year a very young female great white shark was caught accidentally in a fisherman’s net off Huntington Beach, California, and then kept in an ocean pen(栏栅)for 25 days.After being moved to the Monterey Bay Aquarium (水族馆), she grew well in the million-gallon Outer Bay Exhibit.She was so lovely that people all liked her very much.Perhaps she was too young to understand that the big tank was not her natural environment, because she didn’t hit her head against the walls in an attempt to swim away as others of her kind have done.And she began to feed almost immediately on small fish offered to her on a pole.In the months that followed, the shark suffered no serious injuries, caught no diseases, and grew noticeably larger, breaking all records for great white sharks in capacity.The longest that any other great white shark had been held was 16 days.

       Until February 23, that is, when she hit and killed a soupfin shark(翅鲨), as she grew bigger and her behavior grew more aggressive, officials at the Aquarium knew the time had come.On March 31, after 198 days in the aquarium, the great white shark was released into the Pacific.

       Scientists still have a lot to learn about sharks, especially great white sharks which are now considered to be in danger.Scientists do know that sharks are necessary to ocean health.Remove any significant animal from the sea food chain and you will risk destroying the balance of nature.

72.We can see that in the film Jaw the shark was once described as ________.

       A.a pet of children         B.a horror to human beings

       C.a friend of the aged      D.a guard of its owner

73.Different from the others of her kind, the young female great white shark was somewhat ________ in the beginning.

       A.terrible and dangerous         B.fierce and cruel

       C.loyal and friendly          D.gentle and lovely

74.By saying that “officials at the aquarium knew the time had come”, the writer probably means that the female great white shark ________.

       A.had to be killed                           B.escaped from the big tank

       C.had to be set free                          D.began to hit and kill other animals

75.What conclusion can be drawn from the text?

       A.We should protect great white sharks as well as other ocean animals.

       B.The female great white shark will be attacked by some other animals.

       C.Great white sharks are becoming more and more

       D.We should kill the enemies of white sharks in the oceans.

 0  24498  24506  24512  24516  24522  24524  24528  24534  24536  24542  24548  24552  24554  24558  24564  24566  24572  24576  24578  24582  24584  24588  24590  24592  24593  24594  24596  24597  24598  24600  24602  24606  24608  24612  24614  24618  24624  24626  24632  24636  24638  24642  24648  24654  24656  24662  24666  24668  24674  24678  24684  24692  151629 

违法和不良信息举报电话:027-86699610 举报邮箱:58377363@163.com

精英家教网