hce_tcu
112年
英文
第 37 題
📖 題組：
【B】 Most of Africa is a series of stable, ancient plateau surfaces, low in the north and west and higher in the south and east. The plateau is composed mainly of metamorphic rock that has been overlaid in places by sedimentary rock. The escarpment of the plateau is often in close proximity to the coast, thus leaving the continent with a generally narrow coastal plain; in addition, the escarpment forms barriers of falls and rapids in the lower courses of rivers that impede their use as transportation routes into the interior. The entire African continent is surrounded by a narrow continental shelf. The lowest point on the continent is 155 meters below sea level in Lake Assal in Djibouti; the highest point is Mt. Uhuru, a peak of Kilimanjaro in Tanzania, at 5,895 meters in elevation. The continent’s largest river is the Nile, which is also the world’s longest river. The largest lake is Victoria, which is the world’s second largest freshwater lake. There are a number of other rivers and lakes throughout the continent. These lakes and major rivers form an important inland transportation system. Geologists have long noted the excellent fit between the coast of Africa at the Gulf of Guinea and the Brazilian coast of South America, and they have evidence that Africa formed the center of a large ancestral supercontinent known as Pangaea. Pangaea began to break apart in the Jurassic period to form Gondwanaland, which included Africa, the other southern continents, and India. South America was separated from Africa 76 million years ago, when the floor of the South Atlantic Ocean was opened up by seafloor spreading. There is also evidence of one-time connections between Northwest Africa and Eastern North America, North Africa and Europe, Madagascar and India, and Southeast Africa and Antarctica. 76 million years is, of course, a blink of an eye in geological time. The long-term future of Africa as a continent is therefore bleak; although we are accustomed to thinking of Africa as an ancient land and as the birthplace of humanity, it is just as susceptible to the geological forces of a cooling planet as the other continents. Having been formed by these forces, it is unlikely that a continent resembling Africa will still exist in 100 million years.
【B】 Most of Africa is a series of stable, ancient plateau surfaces, low in the north and west and higher in the south and east. The plateau is composed mainly of metamorphic rock that has been overlaid in places by sedimentary rock. The escarpment of the plateau is often in close proximity to the coast, thus leaving the continent with a generally narrow coastal plain; in addition, the escarpment forms barriers of falls and rapids in the lower courses of rivers that impede their use as transportation routes into the interior. The entire African continent is surrounded by a narrow continental shelf. The lowest point on the continent is 155 meters below sea level in Lake Assal in Djibouti; the highest point is Mt. Uhuru, a peak of Kilimanjaro in Tanzania, at 5,895 meters in elevation. The continent’s largest river is the Nile, which is also the world’s longest river. The largest lake is Victoria, which is the world’s second largest freshwater lake. There are a number of other rivers and lakes throughout the continent. These lakes and major rivers form an important inland transportation system. Geologists have long noted the excellent fit between the coast of Africa at the Gulf of Guinea and the Brazilian coast of South America, and they have evidence that Africa formed the center of a large ancestral supercontinent known as Pangaea. Pangaea began to break apart in the Jurassic period to form Gondwanaland, which included Africa, the other southern continents, and India. South America was separated from Africa 76 million years ago, when the floor of the South Atlantic Ocean was opened up by seafloor spreading. There is also evidence of one-time connections between Northwest Africa and Eastern North America, North Africa and Europe, Madagascar and India, and Southeast Africa and Antarctica. 76 million years is, of course, a blink of an eye in geological time. The long-term future of Africa as a continent is therefore bleak; although we are accustomed to thinking of Africa as an ancient land and as the birthplace of humanity, it is just as susceptible to the geological forces of a cooling planet as the other continents. Having been formed by these forces, it is unlikely that a continent resembling Africa will still exist in 100 million years.
What is the main idea in the third paragraph?
- A The Jurassic period.
- B Modern geological disturbances in Africa.
- C How the African continent used to be joined with other continents.
- D The formation of Antarctica, Europe, and the Americas.
思路引導 VIP
請觀察第三段中頻繁出現的專有名詞，例如 Pangaea、Brazil、North America 以及 Antarctica 等。作者在提到這些不同的地理區塊時，主要是想描述非洲與它們之間存在著什麼樣的「空間演變」或「歷史關係」呢？
🤖
AI 詳解
AI 專屬家教
恭喜你精準地掌握了這段文字的核心！能從繁雜的地質名詞中識別出段落的主旨，代表你的閱讀理解與資訊篩選能力相當紮實。
大陸飄移與古老連結
第三段的核心在於探討非洲大陸與世界其他陸塊在地理史上的深厚淵源。作者首先從幾何形狀的契合（如幾內亞灣與巴西海岸）切入，進而引入盤古大陸 (Pangaea) 與岡瓦那大陸 (Gondwanaland) 的演變過程。文中具體列舉了非洲與北美、歐洲、印度及南極洲在地質史上的「連結證據」，這些細節都是為了支撐選項 (C) 的核心論點：說明非洲大陸在過去是如何與其他大陸結合在一起的。
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