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六、阅读理解。
主题群:自然生态 子主题:生态特征 语篇类型:说明文 难度:★★
Though oceans cover about 71% of the earth's surface, there's still a lot we don't know about them. Only about 20% of the seafloor has been mapped, and the remaining 80% is still a secret to us. Some scientists even think that 91% of sea animals have yet to be discovered.
So why do we know so little about the deep sea? Well, getting to those depths is very difficult and requires high technology that simply didn't come into being for most of human history. The first submarine(潜水艇), for example, was built in 1620. In fact, for a long time many scientists didn't even think that there could be any life at depths greater than 550 metres and didn't see much need to explore the deep sea. However, this changed in 1862 when life was discovered as far down as 945 metres below sea level with the help of a digging machine. Later, around 4,700 species(物种) unknown before from the ocean floor were discovered.
Since then, high technology has been developed to help explore the deep sea, including satellites. But why is deep-sea exploration still so difficult? Well, at greater depths it is freezing, everything is completely dark, and the pressure can be over 1,000 times greater than that on the surface.
Though we have the difficulties, it's important that we understand the seas. They help control the earth's temperature and produce oxygen ($O_2$) in the air. They can also provide us with information about climate change. Our future depends on learning more about our oceans, and it is possible for us to really understand what is ongoing below the surface.
1. Why are some numbers listed in Paragraph 1?
A. To introduce how important oceans are.
B. To discuss why sea animals have yet to be discovered.
C. To explain that oceans cover a large area of the earth.
D. To show that we have only a little understanding of oceans.
2. What does the underlined word "They" in the last paragraph refer to?
A. Sea animals.
B. The seas.
C. The satellites.
D. Many scientists.
3. What can we learn from the text?
A. It is difficult to build a submarine.
B. The seas have a strong influence on our future.
C. The seas have no lives at a depth of 550 metres.
D. It is easier to go into the deep sea than we think.
主题群:自然生态 子主题:生态特征 语篇类型:说明文 难度:★★
Though oceans cover about 71% of the earth's surface, there's still a lot we don't know about them. Only about 20% of the seafloor has been mapped, and the remaining 80% is still a secret to us. Some scientists even think that 91% of sea animals have yet to be discovered.
So why do we know so little about the deep sea? Well, getting to those depths is very difficult and requires high technology that simply didn't come into being for most of human history. The first submarine(潜水艇), for example, was built in 1620. In fact, for a long time many scientists didn't even think that there could be any life at depths greater than 550 metres and didn't see much need to explore the deep sea. However, this changed in 1862 when life was discovered as far down as 945 metres below sea level with the help of a digging machine. Later, around 4,700 species(物种) unknown before from the ocean floor were discovered.
Since then, high technology has been developed to help explore the deep sea, including satellites. But why is deep-sea exploration still so difficult? Well, at greater depths it is freezing, everything is completely dark, and the pressure can be over 1,000 times greater than that on the surface.
Though we have the difficulties, it's important that we understand the seas. They help control the earth's temperature and produce oxygen ($O_2$) in the air. They can also provide us with information about climate change. Our future depends on learning more about our oceans, and it is possible for us to really understand what is ongoing below the surface.
1. Why are some numbers listed in Paragraph 1?
A. To introduce how important oceans are.
B. To discuss why sea animals have yet to be discovered.
C. To explain that oceans cover a large area of the earth.
D. To show that we have only a little understanding of oceans.
2. What does the underlined word "They" in the last paragraph refer to?
A. Sea animals.
B. The seas.
C. The satellites.
D. Many scientists.
3. What can we learn from the text?
A. It is difficult to build a submarine.
B. The seas have a strong influence on our future.
C. The seas have no lives at a depth of 550 metres.
D. It is easier to go into the deep sea than we think.
答案
1. D 推理判断题。根据“Though oceans cover about 71% of the earth's surface, there's still a lot we don't know about them.”可知，列举的数字表明，尽管海洋覆盖地球表面的71%左右，但是我们对海洋仍然知之甚少。
2. B 代词指代题。根据“Though we have the difficulties, it's important that we understand the seas. They help ...”可知，虽然有困难，但了解海洋是很重要的。此处They指代上文提到的海洋。
3. B 推理判断题。根据“Our future depends on learning more about our oceans, and it is possible for us to really understand what is ongoing below the surface.”可知，海洋对我们的未来有很大影响。
2. B 代词指代题。根据“Though we have the difficulties, it's important that we understand the seas. They help ...”可知，虽然有困难，但了解海洋是很重要的。此处They指代上文提到的海洋。
3. B 推理判断题。根据“Our future depends on learning more about our oceans, and it is possible for us to really understand what is ongoing below the surface.”可知，海洋对我们的未来有很大影响。
解析
【分析】
1. 第1题是推理判断题，需结合第一段内容分析：第一段首句转折指出尽管海洋覆盖地球约71%，但我们对其仍知之甚少，列举的数字（20%海底被测绘、80%未知、91%海洋动物未被发现）均是为支撑这一观点，说明人类对海洋的了解极少，据此判断选项。
2. 第2题是代词指代题，需定位最后一段划线词“They”的前文：前文提到“it's important that we understand the seas”，后文说明“They”的作用，据此确定指代对象。
3. 第3题是推理判断题，需逐一核对选项与原文细节：将每个选项与原文对应内容对比，排除错误选项，选出符合原文的答案。
【解析】
1. 第1题：根据第一段首句“Though oceans cover about 71% of the earth's surface, there's still a lot we don't know about them.”，列举的数字意在说明人类对海洋的了解极少，故选D。
2. 第2题：最后一段划线词“They”的前文提到“the seas”，结合语境“They help control the earth's temperature and produce oxygen...”，可知They指代“the seas”，故选B。
3. 第3题：A项，原文仅说明1620年已有潜水艇，未提及建造潜水艇困难；B项，对应原文“Our future depends on learning more about our oceans”，说明海洋对人类未来影响重大，正确；C项，原文提到过去科学家认为550米以下无生命，但后来发现945米有生命，错误；D项，原文指出深海探索困难，错误，故选B。
【答案】
1. D 2. B 3. B
【知识点】
英语阅读理解、推理判断题、代词指代题
【点评】
本文是关于海洋探索的说明文，题目聚焦阅读理解核心题型：推理判断与代词指代，需学生精准定位原文细节、结合语境分析，整体难度适中，适合中等水平学生练习，能有效考查语篇理解能力。
【难度系数】
0.7
1. 第1题是推理判断题，需结合第一段内容分析：第一段首句转折指出尽管海洋覆盖地球约71%，但我们对其仍知之甚少，列举的数字（20%海底被测绘、80%未知、91%海洋动物未被发现）均是为支撑这一观点，说明人类对海洋的了解极少，据此判断选项。
2. 第2题是代词指代题，需定位最后一段划线词“They”的前文：前文提到“it's important that we understand the seas”，后文说明“They”的作用，据此确定指代对象。
3. 第3题是推理判断题，需逐一核对选项与原文细节：将每个选项与原文对应内容对比，排除错误选项，选出符合原文的答案。
【解析】
1. 第1题：根据第一段首句“Though oceans cover about 71% of the earth's surface, there's still a lot we don't know about them.”，列举的数字意在说明人类对海洋的了解极少，故选D。
2. 第2题：最后一段划线词“They”的前文提到“the seas”，结合语境“They help control the earth's temperature and produce oxygen...”，可知They指代“the seas”，故选B。
3. 第3题：A项，原文仅说明1620年已有潜水艇，未提及建造潜水艇困难；B项，对应原文“Our future depends on learning more about our oceans”，说明海洋对人类未来影响重大，正确；C项，原文提到过去科学家认为550米以下无生命，但后来发现945米有生命，错误；D项，原文指出深海探索困难，错误，故选B。
【答案】
1. D 2. B 3. B
【知识点】
英语阅读理解、推理判断题、代词指代题
【点评】
本文是关于海洋探索的说明文，题目聚焦阅读理解核心题型：推理判断与代词指代，需学生精准定位原文细节、结合语境分析，整体难度适中，适合中等水平学生练习，能有效考查语篇理解能力。
【难度系数】
0.7
