TOEFL全新真试题

READING COMPREHENSION

Questions 1-9

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)g techniques first developed for the offshore oil and

gas industry, the DSDP s drill ship, theGlomar 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 hundred 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