21. What can be learned about donkeys from paragraph 1?
- A. They seemed mysterious to human ancestors.
- B. They underwent multiple domestication events.
- C. They were tamed at an earlier time than horse.
- D. They were vividly portrayed by ancient travelers.
答案：C
答案句：Now, researchers have used genomes of over 200 donkeys to trace their domestication back to a single event around 7,000 years ago in East Africa—about 3,000 years before humans tamed horses.
参考译文：现在，研究人员利用200多头驴的基因组，将其驯化追溯到大约7000年前东非的一次单一事件——比人类驯化马早了约3000年。
定位线索：题干“from paragraph 1”→答案句取自第1段“...about 3,000 years before humans tamed horses”；文中“before humans tamed horses”对应选项C“They were tamed at an earlier time than horse”（比马更早被驯化）。
解析：题干问从第一段能得知驴的什么信息。答案句明确指出驴的驯化发生在约7000年前，比人类驯化马早约3000年，直接对应选项C。选项A“对人类祖先显得神秘”偷换概念，原文说驯化地点和时间是谜，而非驴本身神秘；选项B“经历多次驯化事件”与原文“a single event”（单一事件）矛盾；选项D“被古代旅行者生动描绘”无中生有，原文未提及。
22. What message is conveyed in Brooks' statement?
- A. The earliest habitats of donkeys are hardly traceable.
- B. It is increasingly easy to read donkeys' DNA sequences.
- C. Written accounts contain vital dues for donkey research.
- D. Genetic analysis offers insight into the history of donkeys.
答案：D
答案句：“Through their DNA, the animals are telling their history themselves,” co-author Samantha Brooks, an equine researcher at the University of Florida, says in a statement “We usually only get the human's side of history through written accounts, but of course written history does not always record exactly how something happened. Looking at these DNA sequences, we get a biological testimony to the environment these animals lived in and the experiences they survived.”
参考译文：“通过它们的DNA，这些动物在讲述它们自己的历史，”合著者、佛罗里达大学马科动物研究员萨曼莎·布鲁克斯在一份声明中说。“我们通常只能通过书面记载了解人类方面的历史，但书面历史当然并不总是准确记录事情是如何发生的。通过观察这些DNA序列，我们获得了这些动物所生活的环境和它们所经历的生存考验的生物学证词。”
定位线索：题干“Brooks' statement”→答案句取自第2段布鲁克斯的引言；文中“Through their DNA, the animals are telling their history themselves”和“we get a biological testimony”对应选项D“Genetic analysis offers insight into the history of donkeys”（基因分析提供对驴历史的洞察）。
解析：题干问布鲁克斯的陈述传达了什么信息。答案句中布鲁克斯明确说“通过DNA，动物在讲述自己的历史”，并强调DNA序列提供了“生物学证词”，说明基因分析能揭示驴的历史，对应选项D。选项A“驴的最早栖息地难以追踪”与原文主旨相反，原文正是通过基因追踪到了东非；选项B“读驴的DNA序列越来越容易”无中生有，原文未提及难易程度；选项C“书面记载包含驴研究的关键线索”与原文矛盾，布鲁克斯说书面历史“并不总是准确记录”，且强调DNA而非书面记载。
23. In their study, the researchers investigated how donkeys?
- A. dispersed widely in the world.
- B. survived with the help of herders.
- C. developed certain behavioral traits.
- D. adapted to the changing environment.
答案：A
答案句：The researchers examined 207 genomes from modern donkeys living in 31 countries across the globe. They also looked at genomes from 15 wild equids and 31 earlier donkeys that lived between about 4,000 and 100 years ago. The team reconstructed the animals' evolutionary tree and used computer models to pinpoint the domestication event: when herders in Kenya and the Horn of Africa tamed wild asses. They then traced how the animals spread across the rest of the continent into Europe and Asia about 2,500 years later.
参考译文：研究人员检查了来自全球31个国家的207头现代驴的基因组。他们还研究了15种野生马科动物和31头生活在约4000至100年前的早期驴的基因组。该团队重建了这些动物的进化树，并使用计算机模型确定了驯化事件：肯尼亚和非洲之角的牧民驯化了野驴。随后，他们追踪了这些动物如何在大约2500年后传播到非洲大陆其他地区，进入欧洲和亚洲。
定位线索：题干“In their study, the researchers investigated how donkeys”→答案句取自第3段“They then traced how the animals spread across the rest of the continent into Europe and Asia”；文中“spread across”对应选项A“dispersed widely in the world”（在世界广泛散布）。
解析：题干问研究人员在研究中调查了驴的什么方面。答案句明确说“他们追踪了这些动物如何传播到非洲大陆其他地区，进入欧洲和亚洲”，即驴的扩散过程，对应选项A“在世界广泛散布”。选项B“在牧民帮助下生存”偷换概念，原文说牧民驯化驴，但未提“帮助生存”；选项C“发展出某些行为特征”无中生有，原文未涉及行为特征；选项D“适应变化的环境”范围扩大，原文虽提到驯化与撒哈拉变干有关，但研究重点是扩散而非适应。
24. As to why the original domestication of donkeys happened, Orlando?
- A. challenges conventional ideas.
- B. provides a possible explanation.
- C. calls for evidence from the Sahara.
- D. holds a different view from Kreier.
答案：B
答案句：Though it's still unclear why the original domestication happened, Science News' Freda Kreier reports that the event coincided with the Sahara growing larger and drier. “Donkeys are champions when it comes to carrying stuff and are good at going at Paul Sabin deserts,” co-author Ludovic Orlando, an evolutionary biologist at Paul Sabin University in France, tells the publication. Prehistoric humans may have tamed donkeys' help navigate the expanding Sahara.
参考译文：尽管最初的驯化为何发生仍不清楚，但《科学新闻》的弗雷达·克赖尔报道称，这一事件恰逢撒哈拉沙漠变得更大更干燥。“驴在驮运东西方面是冠军，而且擅长穿越沙漠，”合著者、法国保罗·萨宾大学的进化生物学家吕多维克·奥兰多告诉该刊物。史前人类可能驯化了驴，以帮助穿越不断扩大的撒哈拉沙漠。
定位线索：题干“As to why the original domestication of donkeys happened, Orlando”→答案句取自第4段奥兰多的引言“Donkeys are champions...”和“Prehistoric humans may have tamed donkeys' help navigate the expanding Sahara”；文中“may have tamed”对应选项B“provides a possible explanation”（提供了一个可能的解释）。
解析：题干问关于驴最初驯化的原因，奥兰多持什么态度。答案句中奥兰多指出驴擅长驮运和穿越沙漠，随后作者总结“史前人类可能驯化了驴”，其中“may”表明这是一个可能的解释，对应选项B。选项A“挑战传统观念”无中生有，原文未提及传统观念；选项C“呼吁从撒哈拉寻找证据”偷换概念，原文只是提到撒哈拉变干，未呼吁寻找证据；选项D“与克赖尔持不同观点”无中生有，克赖尔只是报道事件与撒哈拉变干巧合，奥兰多并未反驳。
25. The authors think that their research could help with
- A. greater protection of wildlife.
- B. better management of donkeys.
- C. recovering early types of donkeys.
- D. raising awareness of climate change.
答案：B
答案句：Not only does human-understanding the equines' genetic makeup help reveal their contribution to human history, but it also might improve their management in the future, as climate change alters the planet's environment, write the authors.
参考译文：作者写道，人类了解马科动物的基因组成，不仅有助于揭示它们对人类历史的贡献，而且随着气候变化改变地球环境，还可能改善未来对它们的管理。
定位线索：题干“The authors think that their research could help with”→答案句取自第6段“it also might improve their management in the future”；文中“improve their management”对应选项B“better management of donkeys”（更好地管理驴）。
解析：题干问作者认为他们的研究能帮助什么。答案句明确指出研究“可能改善未来对它们的管理”，直接对应选项B“更好地管理驴”。选项A“更好地保护野生动物”范围扩大，原文说的是“管理”而非“保护”，且特指驴而非所有野生动物；选项C“恢复早期类型的驴”无中生有，原文未提及恢复；选项D“提高对气候变化的认识”偷换概念，原文提到气候变化是背景，但研究目的是改善管理而非提高认识。