The ocean covers most of our planet, yet we know very little about it. Our ocean is as mysterious as it is beautiful. In fact, we have better maps of Mars than we do of the ocean floor. Why? Exploring (探索) the ocean is a really hard job. There’s a lot of ocean—about 1.4 billion trillion litres (升). That’s 1,400,000,000,000,000,000,000!
★ . One of their most important goals is to learn about coral reefs (珊瑚礁), which are home to lots of sea plants and animals.
Do you know that coral is an animal, not a plant? Tiny animals called polyps (珊瑚虫) build the hard part of the coral as a home to live in. They are called “architects” in the ocean.
However, many coral reefs around the world are in danger. That’s where a clever method called “coral gardening” comes in—giving reefs a second chance. Here’s how it works in four steps:
First, scientists collect small pieces of coral from coral reefs. Then they break them into even smaller ones—tiny pieces grow faster. After that, they place the pieces in lab-controlled or underwater nurseries (苗圃), where tiny pieces are taken good care of. Finally, once strong enough, they are planted onto rock or man-made reefs so that they can grow on their own.
A typical example is the L-shaped Reef. Since 1982, scientists have placed old subway cars into the sea. These strange “homes” have created a huge man-made reef. Now, polyps and fish are moving in!
To know more about the ocean, a volunteer, Paul Green started the Big Bag Project in 2025. It calls on beach visitors to help collect information on plastics and water temperature through a bag which is connected with an app. Next time you go to the beach, take a bag, pick up some rubbish, and have a closer connection with the ocean.
1.1.What does the number in paragraph 1 tell us about the ocean?
A How much salt there is.
B How cold the deep ocean is.
C How large the ocean is.
D How many sea plants there are.
解析：选C。细节理解题
解析：第一段数字描述海洋水体总量巨大，用来说明海洋的体量、规模之大。A 盐含量，B 深海温度，D 海洋植物数量，文中均未提及。
2.2.Which of the following can be put in ★ ?
A Some sea animals are making a comeback
B The ocean is full of wonders to be discovered
C But many scientists are taking on this challenge
D So protecting the ocean is everyone’s responsibility
解析：选C。还原句子（完形选句）
解析：前文讲探索海洋很难；后文 “他们最重要目标是研究珊瑚礁”，“他们” 指代科学家。C：但许多科学家正在迎接这项挑战，起到承上启下。A 动物回归；B 海洋充满奇观；D 保护海洋人人有责，无法衔接上下文。
3.3.What does the underlined word “architects” mean?
A People who build houses.
B Machines that carry things.
C Workers who collect coral.
D Animals that live in the sea.
解析：选A。词义猜测题
解析：architect 本义是建筑师。文中珊瑚虫建造珊瑚硬壳作为家园，所以 “海洋建筑师” 指建造居所的生物。A 建造房屋的人；B 搬运机器；C 采集珊瑚的工人；D 海洋生物，A 最贴合词义。
4.4. In the picture CORAL GARDENING, what is the third step?
A Breaking.
B Nursing.
C Planting.
D Collecting.
解析：选B。细节理解题
解析：珊瑚园艺四步：①Collect 采集；②Break 分割；③place in nurseries 苗圃培育（nursing）；④Plant 移植。第三步是培育。A 分割，C 种植，D 采集，均不是第三步。
5.5.What’s the writer’s main purpose in writing this passage?
A To introduce the Big Bag Project.
B To show the hidden beauty of the ocean.
C To teach us how to become an ocean biologist.
D To encourage more people to explore the ocean.
解析：选D。主旨大意题
解析：文章介绍海洋奥秘、珊瑚修复项目、大袋子项目，结尾号召大家亲近海洋，写作目的是鼓励更多人探索海洋。A 只讲大袋子项目，片面；B 展示海洋隐藏之美不是核心；C 教大家成为海洋生物学家，文中无此内容。
