📖 原文
(1) Birds that feed in flocks commonly retire together into roosts. The reasons for roosting communally are not always obvious, but there are some likely benefits. In winter especially, (3) it is important for birds to keep warm at night and conserve precious food reserves. (4) One way to do this is to find a sheltered roost. Solitary roosters shelter in dense vegetation (5) or enter a cavity - horned larks dig holes in the ground and ptarmigan burrow into snow (6) banks - but the effect of sheltering is magnified by several birds huddling together in (7) the roosts, as wrens, swifts, brown creepers, bluebirds, and anis do. Body contact reduces (8) the surface area exposed to the cold air, so the birds keep each other warm. Two kinglets huddling together were found to reduce their heat losses by a quarter, and three (10) together saved a third of their heat. (11) The second possible benefit of communal roosts is that they act as "information (12) centers." During the day, parties of birds will have spread out to forage over a very large (13) area. When they return in the evening some will have fed well, but others may have (14) found little to eat. Some investigators have observed that when the birds set out again next (15) morning, those birds that did not feed well on the previous day appear to follow those (16) that did. (22) Finally, there is safety in numbers at communal roosts since there will always be a few (23) birds awake at any given moment to give the alarm. But this increased protection is (24) partially counteracted by the fact that mass roosts attract predators and are especially (25) vulnerable if they are on the ground. Even those in trees can be attacked by birds of prey. (26) The birds on the edge are at greatest risk since predators find it easier to catch small (27) birds perching at the margins of the roost.
❓ 试题解析
问题 9： What does the passage mainly discuss?
A. How birds find and store food
B. How birds maintain body heat in the winter
C. Why birds need to establish territory
D. Why birds gather together at night
✅ 正确答案： D）Why birds gather together at night
📝 解析：全文讨论鸟类夜间集群栖息的三个可能好处：保暖、信息共享、安全。
💡 解题技巧：主旨题看首段主题句及全文反复出现的关键词。
问题 10：</： The word "conserve" in line 3 is closest in meaning to
A. retain
B. watch
C. locate
D. share
✅ 正确答案： A）retain
📝 解析："conserve precious food reserves" — conserve = 保存/保留，即 retain。
💡 解题技巧：词汇题结合搭配。
问题 11： Ptarmigan keep warm in the winter by
A. huddling together on the ground
B. burrowing into dense vegetation
C. digging holes in the snow
D. burying themselves in the snow
✅ 正确答案： D）burying themselves in the snow
areserves" — conserve = 保存/保留，即 retain。
💡 解题技巧：细节题定位动物名称和动作。
问题 12： The word "magnified" in line 6 is closest in meaning to
A. caused
B. modified
C. intensified
D. combined
✅ 正确答案： C）intensified
📝 解析："the effect of sheltering is magnified by several birds huddling together" — magnified = 增强/放大。
💡 解题技巧：词汇题：magnify = intensify = 增强。
问题 13： The author mentions kinglets in line 9 as an example of birds that
A. protect themselves by nesting in holes
B. nest with other species of birds
C. nest together for warmth
D. usually feed and nest in pairs
✅ 正确答案： C）nest together for warmth
📝 解析：两个或三个戴菊鸟挤在一起减少热量损失，支持集群保暖的观点。
💡 解题技巧：例证题看例子前的论点句。
问题 14： The word "forage" in line 12 is closest in meaning to
A. fly
B. assemble
C. feed
D. rest
✅ 正确答案： C）feed
📝 解析："spread out to forage over a very large area" — forage = 觅食。
💡 解题技巧：词汇题结合鸟类行为：觅食。
问题 15： Which of the following statements about lesser kestrels is true according to the passage?
A. They hunt in a familiar small hunting ground.
B. They learn from other kestrels where to find food.
C. They hunt alone and roost in flocks.
D. They hunt vertebrates and insects.
✅ 正确答案： B）They learn from other kestrels where to find food.
📝 解析："the lesser kestrel roosts and hunts in flocks, possibly so that one bird can learn from others where to find insect swarms"。
💡 解题技巧：细节判断题定位"lesser kestrel"（lines 19-21）。
问题 16： The common kestrel differs from the lesser kestrel in that
A. it is smaller in size
B. it is a migratory bird
C. it hunts alone
D. it feeds on insects
✅ 正确答案： C）it hunts alone
📝 解析：文中明确"common kestrel roosts and hunts alone"（line 19-20）。
💡 解题技巧：对比题抓比较词。
问题 17： The passage supports which of the following conclusions about the benefits of communal roosts?
A. The benefits of huddling for warmth are greater than other benefits.
B. Protection from predators is the most important benefit.
C. Information sharing is a benefit that occurs only in some species.
D. The benefits of communal roosts are not all equally valid for every species.
✅ 正确答案： D）The benefits of communal roosts are not all equally valid for every species.
📝 解析：文中红隼的例子说明不同物种受益不同：common kestrel 单独栖息，lesser kestrel 集群栖息以共享信息。
💡 解题技巧：推理题结合作者提供的对比例子。
问题 18： Which of the following is a disadvantage of communal roosts that is mentioned in the passage?
A. Diseases easily spread among the birds.
B. Groups are more attractive to predators than individual birds are.
C. Food supplies are quickly depleted.
D. Some birds in the group will attack the others.
✅ 正确答案： B）Groups are more attractive to predators than individual birds are.
📝 解析："mass roosts attract predators and are especially vulnerable"。
💡 解题技巧：缺点题找转折或让步词。
问题 19： The word "they" in line 25 refers to
A. a few birds
B. mass roosts
C. predators
D. trees
✅ 正确答案： B）mass roosts
📝 解析："Even those in trees can be attacked..." — those 指代前文的 mass roosts。
💡 解题技巧：代词题回溯最近的名词短语作主语。
🌐 中文翻译
成群觅食的鸟类通常一起回到栖息地。集群栖息的原因并不总是显而易见，但有一些可能的好处。尤其在冬季，鸟类夜间保持温暖并保存宝贵的食物储备非常重要。实现这一点的一种方法是找到一个有遮蔽的栖息地。单独栖息的鸟类躲在茂密的植被中或进入洞穴——角百灵在地上挖洞，雷鸟钻进雪堆——但几只鸟挤在栖息地中会放大遮蔽的效果，正如鹪鹩、雨燕、褐旋木雀、蓝鸲和 ani 鸟那样。身体接触减少了暴露在冷空气中的表面积，所以鸟儿们互相保暖。研究发现两只戴菊鸟挤在一起可减少四分之一的热量损失，三只在一起可节省三分之一的热量。 集群栖息的第二个可能好处是它们充当"信息中心"。白天，成群的鸟儿会分散到很大的区域觅食。当它们晚上回来时，有些鸟儿吃得很饱，但其他的可能没找到什么食物。一些研究者观察到，第二天早上鸟儿再次出发时，前一天吃得不好的那些鸟儿会跟着吃得好的那些。普通红隼和小红隼的行为可以说明类似鸟类因不同栖息习惯而表现出不同的觅食行为。普通红隼在一个小而熟悉的狩猎场捕食脊椎动物，而小红隼在一片广阔的区域以昆虫为食。普通红隼单独栖息和捕猎，但小红隼集群栖息和捕猎，可能是为了让一只鸟可以从其他鸟那里学到在哪里找到昆虫群。 最后，集群栖息还有数量的安全性，因为在任何特定时刻总会有几只鸟醒着发出警报。但这种增强的保护被一个事实部分抵消：大规模栖息地会吸引捕食者，并且如果在地面上尤其容易受到攻击。即使是树上的集群也可能被猛禽攻击。边缘的鸟类风险最大，因为捕食者更容易抓到栖息在栖息地边缘的小鸟。
🏷️ 标签：#托福阅读 #真题解析 #备考资料
