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
inaccessible
, hidden beneath waters averaging over 3, 600 meters deep. Totally without light and subjected to 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
outer space
.
Although researchers have taken samples of deep-ocean rocks and sediments for over a century, the first detailed global investigation of the ocean bottom did not actually start until 1968, with the beginning of the National Science Foundation's Deep Sea Drilling Project (DSDP). Using techniques first developed for the offshore oil and gas industry, the DSDP's drill ship, the Glomar Challenger, was able to maintain a 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 completed 96 voyages in a 15-year research program that ended in November 1983. During this time, the vessel logged 600, 000 kilometers and took almost 20, 000 core samples of seabed sediments and rocks at 624 drilling sites around the world. The Glomar Challenger's core samples have allowed geologists to reconstruct what 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 on the theories of plate tectonics and continental drift that explain many of the geological processes that shape the Earth.
The cores of sediment drilled by the Glomar Challenger have also yielded information critical to understanding the world's past climates. Deep-ocean sediments provide a climatic record stretching back hundreds of millions of years, because
they
are largely isolated from the mechanical erosion and the intense chemical and biological activity that rapidly destroy much land-based evidence of past climates. This record has already provided insights into the patterns and causes of past climatic change — information that may be used to predict future climates.
单选题
The author refers to the ocean bottom as a "frontier" in Paragraph 1 because it________.
【正确答案】
D
【答案解析】解析：推断题型。参看第一段第二行…vast frontier that even today is largely unexplored and uncharted．
单选题
The word "inaccessible" underlined in Paragraph 1 is closest in meaning to________.
单选题
The Deep Sea Drilling Project was significant because it was________.
【正确答案】
B
【答案解析】解析：细节题型。参看第二段第一句…the first detailed global investigation of the ocean bottom．
单选题
The word "strength" underlined in Paragraph 3 is closest in meaning to________.
【正确答案】
A
【答案解析】解析：词义题型。on the strength of在……基础上；on the basis of在……基础上。
单选题
The word "they" underlined in Paragraph 4 refers to________.
【正确答案】
C
【答案解析】解析：词义题型。根据上下文，此处的they应是物质名词，因而应选C项。
单选题
Deep-ocean sediments provide better information about the world's past climate because they________.
【正确答案】
A
【答案解析】解析：细节题型。答案出自第四段第二句Deep-ocean sediments provide a climatic record stretching back hundreds of millions of years．．．
单选题
Which of the following is NOT mentioned in the passage as being a result of the Deep Sea Drilling Project?
【正确答案】
D
【答案解析】解析：是非题型。根据第三段第三句The Glomar Challenger’s core samples have allowed geologists to reconstruct what the planet looked like hundreds of millions of years ago…和最后一句…nearly all earth scientists agree on the theories of plate tectonics and continental drift that explain many of the geological processes that shape the Earth．及第四段，可知A、B、C三项正确。选项D在文中未提到。