Question

根据短文内容，从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

Coral reefs

For millions of years, coral reefs have provided homes and food for thousands of different living things. Fish and sea birds share the reef with other sea creatures. Now these beautiful places are in danger. 1. Scientists have found that people and pollution have ruined more than one-fourth of the earth’s coral reefs. Unless things change, all of the remaining reefs may die within your lifetime.

Some people think that coral is stone because of its rough, hard surface. But coral is an animal! Tiny polyps (水螅体) form the coral reefs. 2. These colours come from the algae (海藻)  living inside the coral. Billions of coral polyps stick together. New ones grow on the dead corals. This happens year after year. Over time, the coral builds up a reef. The reef rises from the ocean floor until it almost reaches the sea’s surface. It takes coral 500,000 years to build a huge reef. 3. 

The coral reefs have been harmed in different ways. People have broken off pieces of coral. They wanted to sell or keep them. To catch more fish, people have dropped sticks of dynamite (炸药) into the water. 4. Water pollution has encouraged overgrowth of the sea plants that grow near coral reefs. They block out the sunlight that the algae need. 5. Warm water kills the algae. When the algae die, the coral loses both its food and its color. The coral turns white and dies. Scientists call this coral bleaching (珊瑚白化). The bleached part of the coral reef cannot recover.

A. They come in many colours.

B. This has blown up parts of the reefs.

C. So are all the sea plants and animals that depend on them.

D. The worst problem is the heating up of the world’s oceans.

E. Coral reefs are experiencing a rapid increase in most locations.

F. However, it has taken human beings less than 100 years to destroy the reefs.

G. They cover less than 1% of the ocean floor, but support about 25% of sea creatures.

Answer

1.C

2.A

3.F

4.B

5.D

【解析】

试题分析：本文是说明文。文章主要介绍了珊瑚礁的形成及人类对珊瑚礁的破坏。

1.C由该空前的Fish and sea birds ... these beautiful places are in danger可知，珊瑚礁处于危险中，依赖珊瑚礁生存的海洋植物和动物也处在危险中，所以答案是C。

2.A由该空后的These colours come from ...可知，设空处指“珊瑚色彩斑斓”，所以答案是A。

3.F 由该空前的It takes coral 500,000 years to build a huge reef以及下一段的描述可知，珊瑚需要花50万年的时间才能形成巨大的珊瑚礁，而人类用不到100年的时间就开始破坏它，所以但是F。

4.B由该空前的people have dropped sticks of dynamite into the water可知，这样会炸毁部分珊瑚礁，所以答案是B。

5.由该空后的Warm water kills the algae可知，最糟糕的问题是世界海洋的升温，所以答案是D。

考点：自然类阅读。