Questions are based on the recording you have just heard. ________

单选题Questions are based on the recording you have just heard.
_________

A．Major changes in the migration routes of hummingbirds.
B．The adaptation of hummingbirds to urban environments.
C．Concern about the reduction of hummingbird habitats.
D．The impact of ecotourism hummingbird populations.

参考答案C

解析:Today, I wanna begin talking about what happens when habitat is reduced across a large area. There are, of course, animal species that require large areas of habitat, and some migrate over very long distances. [16] So what's the impact of habitat loss on those animals--animals that need large areas of habitat? Well, I'll use the hummingbirds as an example.
Now you know a hummingbird is amazingly small, but even though it's really tiny, it migrates over very long distances, travels up and down the western hemisphere--the Americas, back and forth between where it breeds in the summer and the warmer climates where it spends the winter. So we would say that this whole area over which it migrates is its habitat because on this long-distance journey, it needs to come down to feed and sleep every so often, fight? So hummingbirds have to rely on plants in their natural habitat. And it goes without saying.
[17] But the problem, well, as natural habitat along these migration routes is developed by humans for housing or agriculture or cleared for raising cattle, for instance, there is less food available for migrating hummingbirds. Their nesting sites are affected too, the same, by the same sorts of human activities. And all of these activities pose a real threat to the hummingbird population.
So to help them survive, we need to preserve their habitats. [18] And one of the concrete ways people have been doing this is by cleaning up polluted habitat areas and then replanting flowers, urn, replanting native flowers that hummingbirds feed on.
Promoting ecological tourism is another way to help save their habitat. But to understand more about how to protect and support hummingbirds the best we can, we've got to learn more about their breeding,nesting sites and migration routes, and also about the natural habitats we find there.
A good research method, a good way to leam more,is by running a banding study. These bands are perfectly safe, and some hummingbirds have worn them for years with no evidence of any problems. [19] The band is labeled with a tracking number, oh, and there is a phone number on the band for people to call for free, to report a banded bird they've found or recaptured. So when a banded bird is recaptured and reported, we learn about its migration route, its growth, and how long it has been alive, its lifespan. And findings like these have been of interest to biologists and environmental scientists in a number of countries who are trying to understand the complexities of how changes in a habitat affect the species in it.
【预测】选项均为概括性较强的名词短语表明，本题可能考查录音的主旨。
【解析】C。教授首先提出本次谈论的主要话题是栖息地减少对一些动物的影响，接着以蜂鸟(hummingbirds)为例重点讲述了人类活动对蜂鸟的栖息地所造成的威胁，并涉及一些相关的拯救措施，故答案为C。

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单选题 ___________

A．An increase in the ecotourism industry.
B．An increase in the use of land to raise crops and cattle.
C．A decrease in relative studies about their protection.
D．A decrease in the distance traveled during migration.

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单选题 ___________

A．They have built a series of hummingbird feeding stations.
B．They have supported new laws that punish polluters of wildlife habitats.
C．They have replanted native flowers in once polluted areas.
D．They have learned to identify various hummingbird species.

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单选题 ___________

A．Receiving radio signals from electronic tracking devices.
B．Being contacted by people who recapture banded birds.
C．Counting the birds that return to the same region every year.
D．Comparing old and young birds' migration routes.

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