第一节（共8小题；每小题2分，共16分）
阅读下面短文，从每题所给的四个选项（A、B、C、D）中，选出最佳选项。
A
As people get older, the types of friends they have tend to change. As young adults, humans have a lot of friends. With age, they often prefer to spend their time with just a few close, positive individuals. Researchers long believed that this change was unique to humans, but a new study finds that chimps also have similar tendencies.
One explanation for the humans to get picky about social connections has to do with awareness of our limited life span. “People monitor how much time we have left in our life and choose emotionally-fulfilling relationships in old age,” says one of the study's lead authors Alexandra G. Rosati, a psychologist at the University of Michigan. As people age, they don’t want to be surrounded by a large group of negative friends, but would prefer to be near a handful of optimistic individuals.
Rosati and her colleagues were curious whether chimps would show similar features even though they don’t seem to be aware of their upcoming death. Researchers used 78, 000 hours of observations made over 20 years from the Kibale Chimpanzee Project in Uganda. The data looked at the social interactions of 21 male chimps between 15 and 58 years old. The researchers only studied male chimps because they show stronger social bonds and have more social interactions than female chimps.
Researchers found that wild chimpanzees share a similar pattern. “They interact with others in more positive ways as they get older. Younger adults, in contrast, show more aggression and were more likely to form one-sided relationships where their partner did not reciprocate. ”says Rosati. For example, the older chimpanzees would sit close to their long-time companions and groom (给……梳毛) each other, while younger chimps had more one-sided relationships where they would groom a friend, but the action wasn't returned. The study was published in the journal Science.
“This aging pattern may be the result of shared changes in our abilities to manage our emotions with age,” Rosati says. “This shared pattern between chimpanzees and humans could represent an adaptive response where older adults focus on important social relationships that provide benefits and avoid interactions that have negative consequences as they lose competitive fighting ability.”
21. Why do humans change their preference for friends in old age?
A. Their friends pass away one by one. B. They know their life is running out.
C. They adapt to the changes in nature. D. They don’t like making new friends.
22. What is the purpose of Paragraph 3?
A. To show the study was done scientifically.
B. To show how scientists tried to prove their assumption.
C. To show how hard it was to observe the chimps.
D. To show male chimps are unaware of upcoming death.
23. What does the underlined word “reciprocate” in Paragraph 4 mean?
A. Get along well with them. B. Take care of them.
C. Repay their kindness. D. Sit close to them.
24. Which can be a suitable title for the text?
A. People Prefer Positive Partners in Old Age
B. Positive Bonds Benefit Chimps in Many Ways
C. Aging Chimps like Us Get Picky About Friends
D. Chimps Share Similar Tendencies with Humans
