41.IV. Reading Comprehension: 20%
(請注意：在第1篇文章中被標示的( A ) , ( B ) , ( C ) , ( D ) 為第 41題題目設計的一部份。 )
(第 1 篇) One of the most basic concepts in plate tectonics, the study of the movements of
the earth’s crust, is the idea of continental drift. As even small children often realize when
studying an atlas or a globe, the continents as we know them now seem to be pieces of an
enormous jigsaw puzzle. ( A ) This is because the continents were once, in fact, parts of a single
supercontinent called Gondwanaland. For eons, however, they have been moving apart, and the
oceans separating them have been growing wider. In order for the seas to expand, there must be
some mechanism by which the ocean floor can itself spread out to fill the space vacated by the
continents, a process which was finally discovered by scientists in the 1920’s.
( B ) Using sonar, a device that reads the reflected echoes of sound waves, and a specially
developed magnetometer to measure magnetic fields, scientists discovered that the rocks closest
to the mid-ocean ridges were younger than rocks found at a distance. ( C ) Further, closer
inspection revealed that, while the sea floor close to these ridges was relatively free from debris,
marine sediment became thicker as the distance from the ridges increased. Still more advanced
testing uncovered the fact that there were unusually warm currents emanating from the area of
the ridges. All of these pieces of evidence pointed to one inevitable conclusion: new rock was
somehow being born there as the seafloor spread out from these ridges.
So just how is this rock created? Magma (molten lava from the earth’s mantle) flowing up
through the relatively thin crust of the ocean floor meets the cooler ocean water and quickly
coalesces, forming the rock of the mid-ocean ridges. ( D ) Because, however, this new rock has
no place to go, it exerts pressure against the sides of the fissure through which it emerged,
widening the crack and “spreading” the floor of the ocean. It is precisely this mechanism that
forces the continental plates apart, and is responsible, at least in part, for continental drift.
【題組】41. The following sentence--As is often the case, advances in technology led the way to
scientific knowledge—can be integrated into the passage. Please choose one from the
( A )( B )( C )( D ) marked in the passage, where the sentence can best fit in .