四、阅读理解
Oceans cover about 71 per cent of the earth's surface, but here's a lot we don't know about them. Only about 20 per cent of the seafloor has been mapped (绘图), and the rest 80 per cent is still a secret (秘密) to us. Some scientists even think we only know 10 per cent of the sea animals.
So why do we know so little about the deep sea? Well, getting to the deep water is very difficult and needs high technology (科技). The first navigable submarine (可驾驶的潜水艇) in 1620, for example, couldn't go more than five metres below the surface. In fact, for a long time many scientists didn't even think that there could be any life in the water deeper than 550 metres and didn't see much need to learn about the deep sea. But this changed in 1862 when people found life as far down as 945 metres below sea level (海平面) with the help of a machine. Ten years later, scientists found around 4,700 species (物种) unknown before from the ocean floor.
Now high technology like satellites (卫星) helps us learn more about the deep sea. But why is studying deep sea still so difficult? Well, in deep water, it is freezing (极冷的), everything is completely (完全地) dark, and the pressure (压力) can be over 1,000 times greater than that on the surface.
We have a lot of problems, but it's important to understand the oceans. They help control (控制) the earth's temperature (温度) and produce half of the oxygen ($O_{2}$) in the air. They can also give us information about weather change. Our future largely depends on learning more about our oceans, so we really need to understand what is going on below the surface.
(
A. To introduce how important oceans are.
B. To show why we need to learn about sea animals.
C. To tell that oceans cover a large area of the earth.
D. To show that we know just a little about oceans.
(
A. High technology.
B. Secret species.
C. The clean sea water.
D. Useful information.
(
A. Sea animals.
B. The oceans.
C. The satellites.
D. Many scientists.
(
A. It is difficult to build a navigable submarine.
B. The oceans have a strong influence (影响) on our future.
C. The oceans have no lives 550 metres below sea level.
D. It is easier to go into the deep sea than we think.
Exercise 2 of Unit 6 of 7B Reading ([])
Oceans cover about 71 per cent of the earth's surface, but here's a lot we don't know about them. Only about 20 per cent of the seafloor has been mapped (绘图), and the rest 80 per cent is still a secret (秘密) to us. Some scientists even think we only know 10 per cent of the sea animals.
So why do we know so little about the deep sea? Well, getting to the deep water is very difficult and needs high technology (科技). The first navigable submarine (可驾驶的潜水艇) in 1620, for example, couldn't go more than five metres below the surface. In fact, for a long time many scientists didn't even think that there could be any life in the water deeper than 550 metres and didn't see much need to learn about the deep sea. But this changed in 1862 when people found life as far down as 945 metres below sea level (海平面) with the help of a machine. Ten years later, scientists found around 4,700 species (物种) unknown before from the ocean floor.
Now high technology like satellites (卫星) helps us learn more about the deep sea. But why is studying deep sea still so difficult? Well, in deep water, it is freezing (极冷的), everything is completely (完全地) dark, and the pressure (压力) can be over 1,000 times greater than that on the surface.
We have a lot of problems, but it's important to understand the oceans. They help control (控制) the earth's temperature (温度) and produce half of the oxygen ($O_{2}$) in the air. They can also give us information about weather change. Our future largely depends on learning more about our oceans, so we really need to understand what is going on below the surface.
(
D
) 1. Why are some numbers listed in Paragraph 1?A. To introduce how important oceans are.
B. To show why we need to learn about sea animals.
C. To tell that oceans cover a large area of the earth.
D. To show that we know just a little about oceans.
(
A
) 2. What helps humans learn more about the deep sea?A. High technology.
B. Secret species.
C. The clean sea water.
D. Useful information.
(
B
) 3. What does the underlined word "They" in the last paragraph refer to (指的是)?A. Sea animals.
B. The oceans.
C. The satellites.
D. Many scientists.
(
B
) 4. What can we learn from the text?A. It is difficult to build a navigable submarine.
B. The oceans have a strong influence (影响) on our future.
C. The oceans have no lives 550 metres below sea level.
D. It is easier to go into the deep sea than we think.
Exercise 2 of Unit 6 of 7B Reading ([])
答案：1.D 2.A 3.B 4.B
解析：
【分析】
做这篇阅读理解时，首先可以先快速通读全文，明确文章核心是介绍人类对海洋的认知现状、深海探索的难点以及海洋对地球和人类的重要价值。之后针对每一道题目，带着题干的关键词回到原文对应段落定位内容，逐一比对选项和原文的表述，排除不符合原文的干扰项，就能选出正确答案：比如第1题直接锁定第一段的所有列举数据，分析数据共同指向的结论；第2题定位到介绍探索助力的段落直接找原句；第3题代词指代题要结合代词前后的内容，找符合后文功能描述的指代对象；第4题逐一核对每个选项和原文内容的匹配度，排除错误表述即可。
【解析】
1. 第1题：第一段列举了海洋占地表71%、仅20%的海床被测绘、人类仅了解约10%的海洋生物多组数据，核心目的是直观体现人类对海洋的认知程度极低。A选项第一段没有介绍海洋的重要性，B选项“要了解海洋动物”不是列举所有数据的目的，C选项只片面提到海洋面积大，没有覆盖后面关于人类认知占比的内容，因此选D。
2. 第2题：原文第三段第一句明确表述"Now high technology like satellites helps us learn more about the deep sea"，直接说明高科技是帮助人类更多了解深海的要素，其余选项均不符合原文内容，因此选A。
3. 第3题：划线词"They"的前一句提到"it's important to understand the oceans"，后文描述它们可以调节地球温度、产出大气中一半的氧气，完全符合海洋的功能属性，因此They指代的是海洋，选B。
4. 第4题：逐一核对选项：A选项原文仅提到早期潜水艇下潜深度有限，没有提及建造可驾驶潜水艇难度高；C选项原文说明早期科学家误以为550米以下没有生命，后续已经在更深的海域发现了生命，表述错误；D选项全文都在介绍探索深海的诸多困难，和“比想象中更容易”的表述完全相反；B选项原文最后一段提到"Our future largely depends on learning more about our oceans"，说明海洋对人类未来有极强的影响，表述正确，因此选B。
【答案】
1.D 2.A 3.B 4.B
【知识点】
细节信息查找，代词指代判断，文本推理判断
【点评】
本题是七年级基础科普类阅读理解，整体考点偏向基础，大部分题目都可以通过回原文直接定位得到答案，仅少量题目需要排除和原文相悖的干扰项，主要考察学生快速抓取文本关键信息、理解细节内容的能力，同时也能让学生了解海洋探索的相关科普常识。
【难度系数】
0.85
做这篇阅读理解时，首先可以先快速通读全文，明确文章核心是介绍人类对海洋的认知现状、深海探索的难点以及海洋对地球和人类的重要价值。之后针对每一道题目，带着题干的关键词回到原文对应段落定位内容，逐一比对选项和原文的表述，排除不符合原文的干扰项，就能选出正确答案：比如第1题直接锁定第一段的所有列举数据，分析数据共同指向的结论；第2题定位到介绍探索助力的段落直接找原句；第3题代词指代题要结合代词前后的内容，找符合后文功能描述的指代对象；第4题逐一核对每个选项和原文内容的匹配度，排除错误表述即可。
【解析】
1. 第1题：第一段列举了海洋占地表71%、仅20%的海床被测绘、人类仅了解约10%的海洋生物多组数据，核心目的是直观体现人类对海洋的认知程度极低。A选项第一段没有介绍海洋的重要性，B选项“要了解海洋动物”不是列举所有数据的目的，C选项只片面提到海洋面积大，没有覆盖后面关于人类认知占比的内容，因此选D。
2. 第2题：原文第三段第一句明确表述"Now high technology like satellites helps us learn more about the deep sea"，直接说明高科技是帮助人类更多了解深海的要素，其余选项均不符合原文内容，因此选A。
3. 第3题：划线词"They"的前一句提到"it's important to understand the oceans"，后文描述它们可以调节地球温度、产出大气中一半的氧气，完全符合海洋的功能属性，因此They指代的是海洋，选B。
4. 第4题：逐一核对选项：A选项原文仅提到早期潜水艇下潜深度有限，没有提及建造可驾驶潜水艇难度高；C选项原文说明早期科学家误以为550米以下没有生命，后续已经在更深的海域发现了生命，表述错误；D选项全文都在介绍探索深海的诸多困难，和“比想象中更容易”的表述完全相反；B选项原文最后一段提到"Our future largely depends on learning more about our oceans"，说明海洋对人类未来有极强的影响，表述正确，因此选B。
【答案】
1.D 2.A 3.B 4.B
【知识点】
细节信息查找，代词指代判断，文本推理判断
【点评】
本题是七年级基础科普类阅读理解，整体考点偏向基础，大部分题目都可以通过回原文直接定位得到答案，仅少量题目需要排除和原文相悖的干扰项，主要考察学生快速抓取文本关键信息、理解细节内容的能力，同时也能让学生了解海洋探索的相关科普常识。
【难度系数】
0.85