Just as the soil is a part of the earth,______the atmosphere.A.at it isB.the same isC.so i
Just as the soil is a part of the earth,______the atmosphere.
A.at it is
B.the same is
C.so is
D.and so is
Just as the soil is a part of the earth,______the atmosphere.
A.at it is
B.the same is
C.so is
D.and so is
Just as the soil is part of the earth, ______ the atmosphere.
A.as it is
B.the same is
C.so is
D.and so is
Plants in Desert
Only special plants can survive in the terrible climate of a desert, for these are regions where the annual range of the soil temperature can be over 75℃. Furthermore, during the summer there are few clouds in the sky to protect plants from the sun's ray. Another problem is the fact that there are frequently strong winds which drive small-sharp particles of sand into the plants, tearing and damaging them. The most difficult problem for all forms of plant life, however, is the fact that the entire annual rainfall occurs during a few days or weeks in spring.
Crasses and flowers in desert survive from one year to the next by existing through the long, hot, dry season in the form. of seeds. These seeds remain inactive unless the right amount of rain falls. If no rain falls, or if insufficient rain falls, they wait until the next year, or even still the next. Another factor that helps these plants to survive is the fact that their life cycles are short. By the time that the water from the spring rains disappears--just a few weeks after it falls--such plants no longer need any.
The perennials(多年生植物)have special features which enable them to survive as plants for several years. Thus, nearly all desert perennials have extensive root systems below ground and a small Shoot system above ground. The large root network enables the plant to absorb as much water as possible in a short time. The small shoot system, on the other hand, considerably limits water loss by evaporation (蒸发)。
Another feature of many desert perennials is that after the rainy season they lose their leaves in preparation for the long, dry season, just as trees in wetter climates lose theirs in preparation for the winter. This reduces their water loss by evaporation during the dry season. Then, in the next rainy season, they come fully alive once more, and grow new branches, leaves and flowers, just as the grasses and flowers in desert do.
Ordinary plants can not survive the desert weather as a result of the following EXCEPT for ______.
A.the strong winds
B.the strong sun's ray
C.the long summer days
D.the high soil temperature
根据以下材料,回答题
"Liquefaction" Key to Much of Japanese Earthquake Damage
The massive subduction zone (俯冲带) earthquake in Japan caused a significant level of soil"liquefaction" (液化设施) that has surprised researchers with its __________ (51) severity, a new analysis shows.
"We"ve seen localized examples of soil liquefaction as extreme as this before, but the distance and __________ (52) of damage in Japan were unusually severe," said Scott Ashford, a professor of geotechnical engineering at Oregon State University. "Entire structures were tilted and sinking into the sediments (沉淀物) ," Ashford said. "The shifts in soil destroyed water, drain and gas pipelines, crippling the utilities and infrastructure these communities need to __________ (53). We saw some places that sank as much as four feet."
Some degree of soil liquefaction is common in almost any major earthquake. It"s a phenomenon in which soils soaked with water, particularly recent sediments or sand, can lose much of their __________ (54) and flow during an earthquake. This can allow structures to shift or sink or __________ (55).
But most earthquakes are much __________ (56) than the recent event in Japan, Ashford said. The length of the Japanese earthquake, as much as five minutes, may force researchers to reconsider the extent of liquefaction damage possibly occurring in situations such as this.
"With such a long-lasting earthquake, we saw __________ (57) structures that might have been okay after 30 seconds just continued to sink and tilt as the shaking continued for several more minutes," he said. "And it was clear that younger sediments, and especially areas built on __________ (58) filled ground, are much more vulnerable."
The data provided by analyzing the Japanese earthquake, researchers said, should make it possible to improve the understanding of this soil __________ (59) and better prepare for it in the future. Ashford said it was critical for the team to collect the information quickly, __________ (60) damage was removed in the recovery efforts.
"There"s no doubt that we"ll learn things from what happened in Japanl0 thatl 1 will help us to reduce risks in other similar __________ (61)," Ashford said. "Future construction in some places may make more use of techniques known to reduce liquefaction, such as better compaction to make soils dense, or use of reinforcing stone columns."
Ashford pointed out that northern California have younger soils vulnerable to liquefaction—on the coast, near river deposits or in areas with filled ground. The "young" sediments, in geologic terms, may be those __________ (62) within the past 10,000 years or more. In Oregon, for instance, that describes much of downtown Portland, the Portland International Airport and other cities.
Anything __________ (63) a river and old flood plains is a suspect, and the Oregon Department of Transportation has already concluded that 1,100 bridges in the state are at risk from an earthquake. Fewer than 15 percent of them have been reinforced to __________ (64) collapse. Japan has suffered tremendous losses in the March 11 earthquake, but Japanese construction __________ (65) helped prevent many buildings from collapse- even as they tilted and sank into the ground.
回答(51)题 查看材料
A.internal
B.different
C.difficult
D.widespread
Reinventing the Table
An earth scientist has rejigged the periodic table to make chemistry simpler to teach to students.
(46)But Bruce Railsback from the University of Georgia3 says he is the first to create a table that breaks with tradition and shows the ions of each element rather than just the elements themselves.
"I got tired of breaking my arms trying to explain the periodic table to earth students," he says, criss-crossing his hands in the air and pointing to different bits of a traditional table.(47)But he has added contour lines to charge density, helping to explain which ions react with which.
"Geochemists just want an intuitive sense of what's going on with the elements," says Albert Galy from the University of Cambridge4,(48).
(49)He explains that sulphur, for example, shows up in three different spots -- one for sulphide, which is found in minerals, one for sulphite, and one for sulphate, which is found in sea salt, for instance.
He has also included symbols to show which ions are nutrients, and which are common in soil or water.(50).
A. There have been many attempts to redesign the periodic table since Dmitri Mendeleev2 drew it up in 1871.
B. Railsback has still ordered the elements according to the number of protons they have.
C. "I imagine this would be good for undergraduates."
D. Railsback has listed some elements more than once.
E And the size of element's symbol reflects how much of it is found in the Earth's crust.
F The traditional periodic table was well drawn.
Fifty years ago nature study was not part of the school work; scientific forestry was a
new idea; timber was still cheap because it could be brought in any quantity from distant woodlands; soil destruction and river floods were not national problems; nobody had yet studied long-term climatic cycles in relation to proper land use; even the word "conservation" had nothing of the meaning that it has for us today.
For the sake of ourselves and those who will come after us, we must now set about repairing the mistakes of our forefathers. Conservation should, therefore, be made a part of everyone's daily life. To know about the water table in the ground is just as important to us as a knowledge of the basic arithmetic formulas. We need to know why all watersheds need the protection of plant life and why the running current of streams and rivers must be made to yield their full benefit to the soil before they finally escape to the sea. We need to be taught the duty of planting trees as well as of cutting them. We need to know the importance of big, mature trees, because living space for most of man's fellow creatures on this planet is figured not only in square measure of surface but also in cubic volume above the earth. In brief, it should be our goal to restore as much of the original beauty of nature as we can.
According to the author, the greatest mistake of our forefathers was that______.
A.they had no idea about scientific forestry
B.they were not aware of the significance of nature study
C.they had little or no sense of environmental protection
D.they had no idea of how to make good use of raw materials
Plants in Desert
Only special plants can survive the terrible climate of a desert, for these are regions where the annual range of the soil temperature can be over 75℃. Furthermore, during the summer there are few clouds in the sky to protect plants from the sun's ray. Another problem is the fact that there are frequently strong winds which drive small, sharp particles of sand into the plants, tearing and damaging them. The most difficult problem for all forms of plant life, however, is the fact that the entire annual rainfall occurs during a few days or weeks in spring.
Grasses and flowers in desert survive from one year to the next by existing through the long, hot, dry season in the form. of seeds. These seeds remain inactive unless the right amount of rain falls. If no rain falls, or if insufficient rain falls, they wait until the next year, or even still the next. Another factor that helps these plants to survive is the fact that their life cycles are short. By the time that the water from the spring rains disappears—just a few weeks after it falls—such plants no longer need any.
The perennials have special features which enable them to survive as plants for several years. Thus, nearly all desert perennials have extensive root systems below ground and a small shoot system above ground. The large root network enables the plant to absorb as much water as possible in a short time. The small shoot system, on the other hand, considerably limits water loss by evaporation.
Another feature of many desert perennials is that after the rainy season they lose their leaves in preparation for the long, dry season, just as trees in wetter climates lose theirs in preparation for the winter. This reduces their water loss by evaporation during the dry season. Then, in next rainy season, they come fully alive once more, and grow new branches, leaves and flowers, just as the grasses and flowers in desert do.
Ordinary plants are unable to survive in the desert mainly because of the changeable weather.
A.Right
B.Wrong
C.Not mentioned
Plants in Desert
Only special plants can survive the terrible climate of a desert, for these are regions when the annual range of the soil temperature can be over 75℃. Furthermore, during the summer there are few clouds in the sky to protect plans from the sun' s ray. Another problem is the fact that there are frequently strong winds that drive small, sharp particles of sand into the plants,earing and damaging them. The most difficult probiem for all forms of plant life, however, is the fact that the entire annual rainfall occurs during a few days or weeks in spring.
Grasses and flowers in desert survive from one year to the next by existing through the long, hot, dry season in the form. of seeds. These seeds remain inactive unless the fight amount of'rain falls. If no rain falls, or if insufficient rain falls, they wait until the next year, or even still the next. Another factor that helps these plants to survive is the fact that their life cycles are short. By the time the water from the spring rains disappears — just a few weeks after it falls — such plants no longer need any.
The perennials (多年生植物) have special features that enable them to survive as plants for several years. Thus, nearly all desert perennials have extensive root systems below ground and a small shoot system above ground. The large root network enables the plant to absorb as much water as possible in short time. The small shoot system, on the other hand, considerably limits water loss by evaporation.
Another feature of many perennials is that after the rainy season they 10se their leaves in preparation for the long, dry season, just as trees in wetter climates lose theirs in preparation for the winter. This reduces their water loss by evaporation (蒸发) duing the dry season. Then, in next rainy season, they come fully alive once more, and grow new branches, leaves and flowers, just as the grasses and flowers in desert do.
Ordinary plants are unable to survive in the desert mainly because of the changeable weather.
A.Right
B.Wrong
C.Not mentioned
The Nile is a highway for the people of Egypt. Flat bottomed boats and large narrow barges carry products from one city to another. There are also passenger boats on the Nile, carrying people up and down the river. In ancient times huge blocks of stones were floated down the river on barges. These stones are used in making buildings and monuments.
For thousands of years the Egyptians have depended on the Nile for their crops. The land on both sides of the Nile is desert, where crops cannot be raised. But crops grow well in the Nile Valley. In fact, several different crops are often grown on the same land during the same year.
Once the Nile flooded each year, overflowed its banks, and carried rich soil in land every summer. These floods were caused by early summer rains.
At present there is a series of dams on the Nile. Water raised high in the river each summer as usual. The people do not let the Nile flood, however. They store the water behind dams. It is now possible to use the water as needed, not just at flood time.
In the past______.
A.there was rain all the year long
B.the Nile flooded every year
C.the Nile became deeper and deeper after each rainfall
D.the Nile was not a long river
The word conservation has a thrifty (节俭的) meaning. To conserve is to save and protect, to leave what we ourselves enjoy in such good condition that others may also share the enjoyment. Our forefathers (祖先) had no idea that human population would increase faster than the supplies of raw (天然的) materials; most of them, even until very recently, had the foolish idea that the treasures were "limitless and inexhaustible". Most of the citizens of earlier generations knew little or nothing about the complicated (复杂的), and delicate system that runs all through nature, and which means that, as in a living body, an unhealthy condition of one part will sooner or later be harmful to all the others.
Fifty years ago nature study was not part of the school work; scientific forestry was a new idea; timber was still cheap because it could be brought in any quantity from distant woodlands; soil destruction and river floods were not national problems; nobody had yet studied long-term climatic cycles in relation to proper land use; even the word "conservation" had nothing of the meaning that it has for us today.
For the sake of ourselves and those who will come after us, we must now set about repairing the mistakes of our forefathers. Conservation should, therefore, be made a part of everyone's daily life. To know about the water table in the ground is just as important to us as a knowledge of the basic arithmetic formulas. We need to know why all watersheds need the protection of plant life and why the running current of streams and rivers must be made to benefit the soil fully before they finally escape to the sea. We need to be taught the duty of planting trees as well as of cutting them. We need to know the importance of big, mature trees, because living space for most of man's fellow creatures on this planet is figured not only in square measure of surface but also in cubic volume(立方)above the earth. In brief, it should be our goal to restore as much of the original (原始的) beauty of nature as we can.
The author's attitude towards the present situation in the use of natural resources is______.
A.positive (支持的)
B.neutral (中立的)
C.suspicious (怀疑的)
D.critical (批评的)