52. What do we learn about birds following the traditional migration routes?
- A. They can multiply at an accelerating rate.
- B. They can better pull through the winter.
- C. They help humans kill harmful insects.
- D. They are more likely to be at risk of dying.
答案：D
答案句：Andrea Flack of the Max Planck Institute found that birds following traditional migration routes were more likely to die than German storks that flew only as far as northern Morocco, and spent the winter there on rubbish dumps.
参考译文：马克斯·普朗克研究所的安德烈亚·弗拉克发现，遵循传统迁徙路线的鸟类比那些只飞到摩洛哥北部并在那里的垃圾堆上过冬的德国鹳更可能死亡。
定位线索：题干“birds following the traditional migration routes”→答案句第三段“birds following traditional migration routes were more likely to die”；文中“more likely to die”对应选项D“more likely to be at risk of dying”。
解析：题干问传统迁徙路线的鸟类情况，答案句明确指出它们更可能死亡，对应D选项。A选项“multiply”无中生有，文中未提繁殖；B选项“better pull through”与原文相反，传统路线死亡率更高；C选项“help humans kill harmful insects”答非所问，文中提到白鹳吃蝗虫但未与传统路线鸟类直接关联。
54. What can be inferred about the Spanish birds tagged in the study?
- A. They gradually lose the habit of migrating in winter.
- B. They prefer rubbish dumps far away to those at home.
- C. They are not attracted to the rubbish dumps on their migration routes.
- D. They join the storks from Germany on rubbish dumps in Morocco.
答案：B
答案句：Landfill sites on the Iberian peninsula have long attracted local white storks, but all of the Spanish birds tagged in the study flew across the Sahara desert to the western Sahel.
参考译文：伊比利亚半岛的垃圾填埋场长期以来一直吸引着当地的白鹳，但研究中标记的所有西班牙鸟类都飞越撒哈拉沙漠到达西萨赫勒地区。
定位线索：题干“Spanish birds tagged in the study”→答案句第六段“all of the Spanish birds tagged in the study”；文中“flew across the Sahara desert to the western Sahel”对应选项B“prefer rubbish dumps far away to those at home”（即不选择本地垃圾场而选择远处）。
解析：题干问西班牙标记鸟类的推断，答案句指出尽管本地有垃圾场，但所有西班牙鸟都飞往远处萨赫勒，可推断它们不选择本地垃圾场，对应B选项。A选项“gradually lose the habit”程度过重，仅一次研究无法推断逐渐失去；C选项“not attracted”与原文矛盾，它们飞往远处垃圾场说明仍被吸引；D选项“join storks from Germany”无中生有，文中未提西班牙鸟与德国鸟会合。
55. What is scientists' other concern about white storks feeding on landfills?
- A. The potential harm to the ecosystem.
- B. The genetic change in the stork species.
- C. The spread of epidemics to their homeland.
- D. The damaging effect on bio-diversity.
答案：A
答案句：But that's not the only uncertainty. Migrating birds affect ecosystems both at home and at their winter destinations, and disrupting the traditional routes could have unexpected side effects.
参考译文：但这并不是唯一的不确定性。候鸟影响其栖息地和越冬地的生态系统，而破坏传统路线可能产生意想不到的副作用。
定位线索：题干“scientists' other concern”→答案句第七段“But that's not the only uncertainty”；文中“affect ecosystems”对应选项A“potential harm to the ecosystem”。
解析：题干问科学家对白鹳吃垃圾的其他担忧，答案句指出迁徙鸟类影响生态系统，破坏传统路线有副作用，对应A选项。B选项“genetic change”无中生有，文中未提基因变化；C选项“spread of epidemics”偷换概念，文中未提疾病传播；D选项“bio-diversity”范围缩小，文中泛指生态系统而非仅生物多样性。