___________

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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参考答案

【预测】选项均为描述they的句子，且均为现在完成时表明，本题可能考查they已经做过的事情。
【解析】C。录音中教授提到，人们一直以来所采取的保护蜂鸟栖息地的具体措施之一是：清理受污染的栖息地，然后重新移植蜂乌赖以生存的花卉，故答案为C。

1 ___________

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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2 Questions are based on the recording you have just heard.
___________

A．The rocks cannot move after ice storms.

B．The rocks do not move at night.

C．The rocks never move in circles.

D．The rocks are not moved by people.

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3 ___________

A．Their results were decisive.

B．They were not carried out carefully.

C．They were not continued long enough to reach a conclusion.

D．The government should not have allowed the experiments.

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