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  3. The ocean bottom—a region nearly 2-5 times greater than the total land area

The ocean bottom—a region nearly 2-5 times greater than the total land area

游客2025-01-01  33
问题     The ocean bottom—a region nearly 2-5 times greater than the total land area of the earth—is a vast frontier that even today is largely unexplored and uncharted. Until about a century ago, the deep-ocean floor was completely accessible, hidden beneath waters averaging over 3, 600 meters deep. Totally without light and subjected intense pressures hundreds of times greater than at the Earth’s surface, the deep-ocean bottom is a hostile environment to humans, in some ways as forbidding and remote as the void of out space.
    Therefore researchers have been taking samples of deep-ocean rocks and sediments for over a century, the first detailed global investigation of the ocean bottom did actually start until 1968, with the beginning of the National Science Foundation’s Deep Sea Drilling Project (DSDP). Used techniques first developed for the offshore oil and gas industry, the DSDP’s drill ship, the Glomar Challenger, was able to maintain steady position on the ocean’s surface and drill in very deep waters, extracting samples of sediments and rock from the ocean floor.
    The Glomar Challenger’s core samples have allowed geologists to reconstruct that the planet looked like hundreds of millions of years ago and to calculate what it will probably look like millions of years in the future. Today largely on the strength of evidence gathered during the Glomar Challenger’s voyages, nearly all earth scientists agree with the theories of plate construction and continental drift that explain many of the geology processes that shape the Earth. [br]
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答案 did ∧ actually→not
解析 语义错误。根据上下文，此处应为否定，与后面的until呼应，构成“not…until”的结构，意为“直到1968年，才开始第一次详尽的全球范围的海底考察”。
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