C
Though oceans cover about 71 percent of the earth's surface, there's still a lot we don't know about them. Only about 20 percent of the seafloor has been mapped, and the remaining is still a secret to us. Some scientists even think that 91 percent 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 navigable submarine(可驾驶的潜水艇), for example, was built in 1620, and it 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 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. Ten years later, around 4,700 species 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(极冷的), everything is completely dark, and the pressure can be over 1,000 times greater than that on the surface.
Though we have difficulties, it's important that we understand the seas. They help control the earth's temperature and produce half of the oxygen ($\ce{O_2}$) 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 going on below the surface.
(
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.
(
A. High technology.
B. Unknown species.
C. A pleasant environment.
D. Valuable information.
(
A. Sea animals.
B. The seas.
C. The satellites.
D. Many scientists.
(
A. Hidden treasures in deep sea
B. Unlocked secrets of deep sea
C. Deep-Sea exploration: Into the freezing depths
D. Deep-Sea exploration: The past and the future
Though oceans cover about 71 percent of the earth's surface, there's still a lot we don't know about them. Only about 20 percent of the seafloor has been mapped, and the remaining is still a secret to us. Some scientists even think that 91 percent 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 navigable submarine(可驾驶的潜水艇), for example, was built in 1620, and it 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 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. Ten years later, around 4,700 species 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(极冷的), everything is completely dark, and the pressure can be over 1,000 times greater than that on the surface.
Though we have difficulties, it's important that we understand the seas. They help control the earth's temperature and produce half of the oxygen ($\ce{O_2}$) 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 going on below the surface.
(
D
)33. 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.
(
A
)34. What caused the change of exploration into the deep sea?A. High technology.
B. Unknown species.
C. A pleasant environment.
D. Valuable information.
(
B
)35. What does the underlined word "They" refer to?A. Sea animals.
B. The seas.
C. The satellites.
D. Many scientists.
(
C
)36. What could be the best title for the text?A. Hidden treasures in deep sea
B. Unlocked secrets of deep sea
C. Deep-Sea exploration: Into the freezing depths
D. Deep-Sea exploration: The past and the future
答案：C[语篇解读]本文介绍了了解海洋的重要性。
33. D 推理判断题。根据“Though oceans cover about 71 percent of the earth's surface, there's still a lot we don't know about them.”可知，第一段列举数字是为了表明，尽管海洋覆盖地球的 71％，但是我们仍然知之甚少。
34. A 推理判断题。根据“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.”和“Since then, high technology has been developed to help explore the deep sea, including satellites.”可知，探索深海需要高科技的帮助。
35. B 代词指代题。根据“Though we have difficulties, it's important that we understand the seas.”可知，虽然我们有困难，但了解海洋是很重要的。故此处 They 指代上文的 seas。
36. C 标题概括题。本文主要是关于探索深海的内容，排除 A 和 B；根据“Since then, high technology has been developed to help explore the deep sea, including satellites. But why is deep-sea exploration still so difficult?”可知，本文主要是介绍深海探究的现状，并不是过去与未来。
33. D 推理判断题。根据“Though oceans cover about 71 percent of the earth's surface, there's still a lot we don't know about them.”可知，第一段列举数字是为了表明，尽管海洋覆盖地球的 71％，但是我们仍然知之甚少。
34. A 推理判断题。根据“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.”和“Since then, high technology has been developed to help explore the deep sea, including satellites.”可知，探索深海需要高科技的帮助。
35. B 代词指代题。根据“Though we have difficulties, it's important that we understand the seas.”可知，虽然我们有困难，但了解海洋是很重要的。故此处 They 指代上文的 seas。
36. C 标题概括题。本文主要是关于探索深海的内容，排除 A 和 B；根据“Since then, high technology has been developed to help explore the deep sea, including satellites. But why is deep-sea exploration still so difficult?”可知，本文主要是介绍深海探究的现状，并不是过去与未来。
解析：
【分析】
本题为英语阅读理解题，需结合文章内容分析各题：
1. 第33题：需分析第一段数字的作用，结合首句“虽然海洋覆盖地球71%，但我们仍有很多未知”，判断数字的目的；
2. 第34题：需找探索深海态度变化的原因，结合文章中“高科技发展帮助探索深海”的内容分析；
3. 第35题：需判断代词“They”的指代对象，结合前文提到的“了解海洋很重要”，确定指代内容；
4. 第36题：需概括文章主旨，结合文章围绕深海探索的环境特点展开的内容，选择合适标题。
【解析】
33. 根据第一段“Though oceans cover about 71 percent of the earth's surface, there's still a lot we don't know about them”，列举的数字（71%、20%、91%）是为了说明我们对海洋的了解很少，故选D；
34. 文章提到之前科学家不认为深海有生命，后来因高科技发展帮助探索深海，探索态度发生变化，故选A；
35. 前文提到“Though we have difficulties, it's important that we understand the seas”，此处“They”指代前文的“the seas”，故选B；
36. 文章主要介绍深海探索的困难（极冷、黑暗、高压），A、B偏离主旨，D的“过去与未来”未体现，故选C。
【答案】
33.D 34.A 35.B 36.C
【知识点】
英语阅读理解，推理判断题，代词指代题，标题概括题
【点评】
本文围绕深海探索展开，考查学生对文章细节、逻辑关系、代词指代及主旨大意的理解，需结合上下文分析，难度适中。
【难度系数】
0.5
本题为英语阅读理解题，需结合文章内容分析各题：
1. 第33题：需分析第一段数字的作用，结合首句“虽然海洋覆盖地球71%，但我们仍有很多未知”，判断数字的目的；
2. 第34题：需找探索深海态度变化的原因，结合文章中“高科技发展帮助探索深海”的内容分析；
3. 第35题：需判断代词“They”的指代对象，结合前文提到的“了解海洋很重要”，确定指代内容；
4. 第36题：需概括文章主旨，结合文章围绕深海探索的环境特点展开的内容，选择合适标题。
【解析】
33. 根据第一段“Though oceans cover about 71 percent of the earth's surface, there's still a lot we don't know about them”，列举的数字（71%、20%、91%）是为了说明我们对海洋的了解很少，故选D；
34. 文章提到之前科学家不认为深海有生命，后来因高科技发展帮助探索深海，探索态度发生变化，故选A；
35. 前文提到“Though we have difficulties, it's important that we understand the seas”，此处“They”指代前文的“the seas”，故选B；
36. 文章主要介绍深海探索的困难（极冷、黑暗、高压），A、B偏离主旨，D的“过去与未来”未体现，故选C。
【答案】
33.D 34.A 35.B 36.C
【知识点】
英语阅读理解，推理判断题，代词指代题，标题概括题
【点评】
本文围绕深海探索展开，考查学生对文章细节、逻辑关系、代词指代及主旨大意的理解，需结合上下文分析，难度适中。
【难度系数】
0.5