C Read the magazine article about government programmes to help certain ecosystems and choose the best answer for each question.
Bring back balance
Every ecosystem has a careful balance between its plants and animals. Sometimes, the best way to keep this balance is bringing back a key animal species. This is exactly what some governments did, and the results were amazing!
In 1995, the American government brought wolves back to Yellowstone National Park. These animals were common there until the 1930s, but then hunters killed them all. Without wolves, the number of elk grew quickly, since wolves were their biggest threat. However, there were too many elk in the park, and the elk ate too many willow trees. This was terrible for beavers because they need willow trees to survive in winter. Now, with the wolves back to Yellowstone, there are fewer elk, more willow trees—and happier beavers!
A similar thing happened in Scotland. In 2009, the government introduced beavers to the country. Beavers used to live in Scotland, but hunters killed the last ones in the 16th century. Since they were introduced to Scotland, the new beavers have helped improve the environment. To build their homes, beavers bite down small trees. This allows more light to reach other plants and helps them grow. Beavers also create small ponds. These provide homes for all kinds of insects and birds. Finally, beavers often build dams to slow down the flow of river water. This can help stop flooding in the area.
Today, these two ecosystems are both doing well. The examples teach us an important lesson: sometimes, just one type of animal can change the balance of an entire ecosystem.
1 What is the main purpose (目的) of the text?
a To show how one type of animal can change an ecosystem.
b To encourage governments to protect ecosystems.
c To compare different ecosystems.
2 What happened in Yellowstone National Park in 1995?
a Hunters killed the last wolves in the park.
b The American government brought wolves back to the park.
c The elk in the park faced serious threats.
3 What was the main problem for beavers in Yellowstone National Park?
a They couldn’t find enough willow trees.
b Wolves hunted too many of them.
c The government introduced too many of them into the park.
4 Why are beavers important in Scotland?
a Because they help small trees grow.
b Because they reduce the number of insects.
c Because they improve the environment for many plants and animals.
答案：【解析】：
这是一篇英语阅读理解题，主要考查学生对于文章主旨和细节信息的理解能力。文章主要讲述了两个生态系统恢复平衡的例子：一个是美国黄石国家公园通过重新引入狼来恢复生态平衡，另一个是苏格兰通过重新引入海狸来改善环境。题目要求根据文章内容选择最佳答案。
1. 第一题是主旨题，需要理解文章的整体意思，找出文章的主要目的。
2. 第二题是细节题，需要回到文章中找到1995年黄石国家公园发生的事件。
3. 第三题是细节题，需要找出黄石国家公园中海狸面临的主要问题。
4. 第四题是细节题，需要理解海狸在苏格兰的重要性。
【答案】：
1. a
文章主要讲述了通过重新引入一种动物来改变整个生态系统的平衡，因此主要目的是展示一种动物如何改变生态系统。
2. b
根据文章中的句子“In 1995, the American government brought wolves back to Yellowstone National Park.”可知，1995年美国政府将狼重新引入了黄石国家公园。
3. a
文章中提到，“This was terrible for beavers because they need willow trees to survive in winter.”说明海狸在黄石国家公园面临的主要问题是找不到足够的柳树。
4. c
文章中提到海狸在苏格兰帮助改善环境，建造家园时咬下小树，让更多阳光照射到其他植物上，帮助它们生长，还创造了小池塘，为各种昆虫和鸟类提供了家园。因此，海狸对苏格兰的重要性在于它们为许多植物和动物改善了环境。
