问答题
"Pangea"
Read a short passage and then listen to part of a lecture on the same topic.
Reading Time: 45 seconds
{{U}}Pangea{{/U}}
Plate tectonics assumes that the Earth's rigid outer layer is comprised of a number of slabs called plates, which are constantly in motion, changing the position of land masses and seascapes relative to each other throughout history. The plates move slowly but continuously at about the rate of 2 inches every year. The movement of the plates themselves may be caused by the unequal distribution of heat and pressure below them. Very hot material deep within the mantle, that is, the layer of rock inside the Earth, moves upward while the cooler layer descends into the mantle, putting the outer crust of the continents in motion. Several large plates include an entire continent with its surrounding seafloor; however, the boundaries of the plates do not correspond precisely with the seven continents that we recognize today.
Read a short passage and then listen to part of a lecture on the same topic.
Reading Time: 45 seconds
{{U}}Pangea{{/U}}
Plate tectonics assumes that the Earth's rigid outer layer is comprised of a number of slabs called plates, which are constantly in motion, changing the position of land masses and seascapes relative to each other throughout history. The plates move slowly but continuously at about the rate of 2 inches every year. The movement of the plates themselves may be caused by the unequal distribution of heat and pressure below them. Very hot material deep within the mantle, that is, the layer of rock inside the Earth, moves upward while the cooler layer descends into the mantle, putting the outer crust of the continents in motion. Several large plates include an entire continent with its surrounding seafloor; however, the boundaries of the plates do not correspond precisely with the seven continents that we recognize today.
【正确答案】Rexponses will vary.
【答案解析】[解析]
Narrator 2: Read a short passage and then listen to part of a lecture on the same topic. Then listen for a question about them. After you hear the question, you have 30 seconds to prepare and 60 seconds to record your answer.
Narrator 1: Now read the passage about Pangea printed on page 496. You have 45 seconds to complete it. Please begin reading now.
[Reading time: 45 seconds] Narrator 1 : Now listen to part of a lecture in a geography class. The professor is talking about Pangea.
Professor:
The theory of continental drift posits that 250 million years ago the continents were all connected in one gigantic continent, which we refer to as Pangea, and that was surrounded by one huge ocean called Panthalassa. At that time, the northernmost region of the continent corresponded to a landmass that included most of the modern continent of Asia, and Europe was south of the Asian region instead of north as it is now. So Asia and Europe were connected to the west with what is now North America. Africa and the Arabian Peninsula were positioned south of Europe with South America to the west, India to the east, and Antarctica and Australia south and southeast. Then, about 200 million years ago, this super continent began to separate into a northern continent and a southern continent. The northern continent was made of what is currently North America, Greenland, Europe, and Asia, and the southern continent included Antarctica, Australia, India, and South America. By 135 million years ago, the two continents had moved into positions that began to resemble the map that we see today, with seven continents.
Narrator 1 : Explain how plate tectonics relates to the theory of continental drift.
Narrator 2: Please prepare your answer after the beep.
Beep
[Preparation time: 30 seconds]
Narrator 2: Please begin speaking after the beep.
Beep
[Recording time: 60 seconds]
Beep