阅读理解 Since life began eons ago, thousands of creatures have come and gone. Some, such as the dinosaurs, became extinct due to naturally changing ecologic conditions. More recent threats to life forms are humans and their activities. Man has drained marshes, burned prairies, dammed and diverted rivers. Some of the more recent casualties of man''s expansion have been the dodo, great auk, passenger pigeon, Irish elk, and Steller''s sea cow. Sadly, we can no longer attribute the increasing decline in our wild animals and plant species to "natural" processes. Many species are dying out because of exploitation, habitat alteration or destruction, pollution, or the introduction of new species of plants and animals to an area. As mandated by Congress, protecting endangered species, and restoring them to the point where their existence is no longer jeopardized, is the primary objective of the U.S. Fish and Wildlife Service''s Endangered Species Program.

单选题 Which of the following is a form of man's habitat alteration?

【正确答案】 C

【答案解析】细节题型。见文中第三、四句：More recent threats to life forms are humans and their activities．Man has drained marshes，burned prairies，dammed and diverted rivers．各种生物近期遇到的威胁更多来自于人类：人类耗干了湿地、烧毁了大草原、筑坝并让河流改道。因此C．“人类生活环境变迁的一种形式是在河流上筑坝。”为答案，其余A．“冰川侵蚀”、B．“飓风”和D．“暴风雪”均是自然现象。

单选题 Which of the following has become extinct due to man's destruction ?

【正确答案】 B

【答案解析】细节题型。见文中第五句：Some of the more recent casualties of man's expansion have been the dodo，great auk，passenger pigeon，Irish elk，and Steller's sea cow．近期人类扩张所造成的一些受害者有：渡渡鸟、大海雀、候鸽、爱尔兰麋鹿及Steller's海象。本题所问：“由于人类破坏已经灭绝的物种是……”，应为“爱尔兰麋鹿”。

单选题 Which of the following would be a likely theme for the next paragraph?

A、 Naturally changing ecological conditions.
B、 Animals that have become extinct.
C、 Achievements of the government Endangered Species Program.
D、 Programs that have destroyed natural habitats.

【正确答案】 C

【答案解析】推断题型。本段提到了由于生态环境的变迁和人类活动的破坏等因素造成了一些物种的灭绝；段尾提到由国会授权，美国渔业及野生动物署实施挽救濒危物种计划且提到这一计划的主要目标。根据逻辑推理，下段应提及政府实施这一计划所带来的变化，因此选项C．“政府实施这一计划所带来的成就。”应为答案。

单选题 The tone of this passage is________.

【正确答案】 B

【答案解析】态度题型。本文的语气从文章作者所持的态度来看是支持保护野生动植物的，因此选项B．“亲……野生动植物的”是答案。

单选题 According to this passage,________

A、 man is the cause of some animal extinction
B、 animals often bring about their own extinction
C、 Congress can absolutely end extinction of animals
D、 a law is more important than human responsibility

【正确答案】 A

【答案解析】推断题型。文中提到More recent threats to life forms are humans and their activities…．Some of the more recent casualties of man's expansion have been the dodo，great auk，passenger pigeon，Irish elk，and Steller's sea cow．各种生物近期遇到的威胁更多来自于人类。……近期人类扩张所造成的一些受害者有：渡渡鸟、大海雀、候鸽、爱尔兰麋鹿及Steller's海象。因此根据本文，我们能推断出人类是造成某些动物灭绝的原因，所以A是答案。

单选题 Which of the following is NOT a cause of increasing decline of wild animal population?

【正确答案】 D

【答案解析】是非题型。文中提到Many species are dying out because of exploitation，habitat alteration or destruction，pollution，or the introduction of new species of plants and animals to an area．许多物种灭绝是由于人类的开发，栖息地的变更或毁灭，污染或新的动、植物物种的传入。因此选项A．exploitation、B．pollution和C．habitat alteration均是导致野生动物总数持续下降的原因，只有选项D．Congressional law不是原因，故是本题答案。