题目
That the plates are moving is now beyond dispute. Africa and South America, for example, are moving away from each other as new material is injected into the sea floor between them. The complementary coastlines and certain geological features that seem to span the ocean are reminders of where the two continents were once joined. The relative motion of the plates carrying these continents has been constructed in detail, but the motion of one plate with respect to another cannot readily be translated into motion with respect to the earth's interior. It is not possible to determine whether both continents are moving in opposite directions or whether one continent is stationary and the other is drifting away from it. Hot spots, anchored in the deeper layers of the earth, provide the measuring instruments needed to resolve the question. From an analysis of the hot spot population it appears that the African plate is stationary and that it has not moved during the past 30 mil lion years.
The significance of hot spots is not confined to their role as a frame. of reference. It now appears that they also have an important influence on the geophysical processes that propel the plates across the globe. When a continental plate comes to rest over a hot spot, the material rising from deeper layer creates a broad dome. As the dome grows, it develops deed fissures (cracks); in at least a few cases the continent may break entirely along some of these fissures, so that the hot spot initiates the formation of a new ocean. Thus just as earlier theories have explained the mobility of the continents, so hot spots may explain their mutability (inconstancy).
The author believes that ______.
A．the motion of the plates corresponds to that of the earth's interior
B．the geological theory about drifting plates has been proved to be truse
C．the hot spots and the plates move slowly in opposite directions
D．the movement of hot spots proves the continents are moving apart
更多“Scattered around the globe are more than 100 small regions of isolated volcanic activity k”相关的问题
第1题
1.All festivals celebrated in England can date back 100 years or more.()
2.Today, people all over the world know St. Valentine’s Day.()
3.Halloween falls on the end of November.()
4.Symbols of Halloween include ghosts, black cats and witches.()
5.The birthday of Jesus Christ is on December 25.()
第2题
The Building of the Pyramids
The oldest stone buildings in the world are the pyramids.【46】 There are over eighty of them scattered along the banks of the Nile, some of which are different in shape from the true pyramids. The most famous of these are the "Step" pyramid and the "Bent" pyramid.
Some of the pyramids still look much the same as they must have done when they were built thousands of years ago. Most of the damage suffered by the others has been at the hands of men who were looking for treasure or, more often, for stone to use in modem buildings.【47】. These are good reasons why they can still be seen today, but perhaps the most important is that they were planned to last for ever. 【48】. However, there are no writings or pictures to show us how the Egyptians planned or built the pyramids themselves.【49】. Nevertheless, by examining the actual pyramids and various tools which have been found, archaeologists have formed a fairly cleat picture of them.
One thing is certain: there must have been months of careful planning before they could begin to build.【50】 You may think this would have been easy with miles and miles of empty desert around, but a pyramid could not be built just anywhere. Certain rules had to be followed, and certain problems had to be overcome.
A. The dry climate of Egypt has helped to preserve the pyramids, and their very shape have made them less likely to fall into ruin.
B. It is practically certain that plans were made for the building of the pyramid because the plans of other large works have fortunately been preserved.
C. The first thing they had to do was to choose a suitable place.
D. Consequently, we are only able to guess at the methods used.
E. Many people were killed while building the pyramids.
F. They have stood for nearly 5,000 years, and it seems likely that they will continue to stand for thousands of years yet.
(46)
第3题
请根据短文的内容，回答题。
The Building of the Pyramids
The oldest stone buildings in the world are the pyramids. They have stood for nearly 5,000 years, and it seems like that __________ (46). There are over eighty of them scattered along the banks of the Nile, some of which are different in shape from the true pyramids. The most famous of these are the "Step" pyramid and the "Bent" pyramid.＜br＞
Some of the pyramids still look much the same as they must have done when they were built thousands of years ago. Most of the damage suffered by the others has been at the hands of men who were looking for treasure or, more often, __________ (47). The dry climate of Egypt has helped to preserve the pyramids, and their very shape __________ (48). These are good reasons why they can still be seen today, but perhaps the most important is that they were planned to last for ever.＜br＞
It is practically certain that plans were made for the building of the pyramids __________ (49).＜br＞
However, there are no writings or pictures to show us how the Egyptians planned or built the pyramids themselves. Consequently, we are only able to guess at the methods used. Nevertheless,by examining the actual pyramids and various tools which have been found, archaeologists have formed a fairly clear picture of them.＜br＞
One thing is certain: there must have been months of careful planning __________ (50). The first thing they had to do was to choose a suitable place. You may think this would have been easy with miles and miles of empty desert around, but a pyramid could not be built just anywhere.＜br＞
Certain rules had to be followed, and certain problems had to be overcome.＜
第46题___________ 查看材料
A.for stone to use in modem buildings
B.has made them less likely to fall into ruin
C.before they could begin to build
D.because the plans of other large works have fortunately been preserved
E.while building the pyramids
F.they will continue to stand for thousands of years yet
第5题
A.varnished
B.scattered
C.slacked
D.gazed
第6题
A.striped
B.spilled
C.scattered
D.spotted
第8题
A. scraped
B. screamed
C. scattered
D. scanned
第9题
A、scattered
B、enrolled
C、overheard
D、advocated
第10题
The chickens quickly ____ when the fox entered the yard.
A、flew
B、spread
C、ran
D、scattered
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