who are waiting for transplants of critical organs, tissues, skin and bones.

　　Britain's National Health Service (NHS) recently counts 14.3 million organ donors on a list which began in 1994. Not everyone wants to participate, however, according to the NHS, 90 percent of the British strongly support organ donation, but only 23 percent are on the organ-donor list.

　　Why the discrepancy(差异)? One reason is that organ donation is a personal matter. Another reason may be indecision: when families are not sure about a dead relative's wishes, 40 percent decide not to donate his or her organs. Interestingly, religion has little to do with a decision not to donate. All six of the main religions in Britain support organ donation and transplantation.

　　The government decided in 2018 how the system of organ donation should work--- without a policy of presumed consent. Opinion among members of parliament (议会) continues to be divided; but the tragedy goes on: as things are now, one in 10 Britons in need of an organ will never get one.

24. What does the tragedy in Para.1 refer to?

A. People are required to be organ donors.

B. Organ transplants could save lives for more than 60 years.

C. More and more donors' organs are not proper for operation.

D. Many patients have to die because of no replacement organ.

25. The underlined words "opt out" in Para. 2 mean"_______".

A. criticize on donating their organs B. accept organ transplants operation

C. persuade their parents not to donate D. choose to be out of the organ donors

26. According to Para. 4, most British people______.

A. support organ donation without action B. want to participate in organ donation

C. are willing to donate their organs D. don't like NHS' activity

27. What' s the main idea of the passage?

A. Analyzing the tragedy of organ donation.

B. Persuading people to support organ donation.

C. Praising those people who donate their organs.

D. Listing government' s measures on organ donation.

C

　　When she was studying to become a scientist, Megan Strauss rode in a small airplane to study giraffes. While a pilot flew over the Serengeti in Tanzania, Africa, the researchers looked down carefully and counted giraffes.

　　"I am always amazed how easily we can spot warthogs and other small animals, yet we sometimes have trouble seeing giraffes. Giraffes are slender in shape, and they may not throw a good shadow, " says Dr. Strauss, who has since become a wildlife scientist.

　　The Serengeti is about the size of Vermont, a state in the northeastern US, so the scientists could not study the entire area. Instead, they surveyed three areas where giraffes were studied in the 1970s. As they expected, they saw far fewer of these animals.

　　To find out if lions had been killing more giraffes in recent years, the team looked at the survival of young giraffes. Lions kill more young giraffes than adults, but the team found no decrease in young giraffes' survival after they are born, compared with the 1970s.

　　The team then looked at whether too many giraffes were being killed by parasites(寄生虫）.The researchers counted parasite eggs in giraffe droppings, and they found too few to harm the giraffe population.

　　They looked into whether poachers (盗猎者)were killing too many giraffes. Two of the areas they studied are where giraffe meat is sometimes sold in local markets. Poachers catch more adult males than other giraffes. Researchers spotted too few males compared with females in those two areas, a sign of poaching.

When the food supply is short, the environment supports fewer giraffes and the females have