Land and water used to produce 2）____________.

The biggest hovercraft, which can be used on both land and water, might be ______.

A．the sidewall ACV

B．Mountbatten Class hovercraft

C．Cockerell's ACV

D．Sedam N500

___.

A.mean sea level

B.mean high water

C.mean low water

D.half-tide level

What's the main idea of the second paragraph？______

A．Fossil energy was once very cheap

B．Farms in dry areas could get cheap water

C．Most American farmers used too much fertilizer and pesticide

D．Mainstream American agriculture used to be wasteful of energy, water and land

The second paragraph focuses on the fact that ______.

A．fossil energy was once very cheap

B．farm in dry areas could get cheap water

C．most American farmers used too much fertilizer and pesticide

D．mainstream American agriculture used to be wasteful of energy, water and land

he right direction？ Choose 3 answers.

A．Using magnetic fields as a guide

B．Recognizing coastal landmarks

C．Following the heat of the tropical water

D．Listening to sounds that bounce off of the land

E．Following the migrating plankton

It can be inferred from the passage that calcium carbonate shells______

A．are not as susceptible to deterioration as rocks

B．are less common in sediments formed during an ice age

C．are found only in areas that were once covered by land ice

D．contain radioactive material that can be used to determine a sediment’s isotopic composition

E．reflect the isotopic composition of the water at the time the shells were formed

ing is harmful to local wildlife. To produce the same amount of food, however, more land must be under cultivation when organic farming techniques are used than when chemicals are used. Therefore, organic farming leaves less land available as habitat for local wildlife. Which one of the following is an assumption on which the authors argument depends？

A．Chemical fertilizers and pesticides pose no health threat to wildlife.

B．Wildlife living near farms where chemicals are used will not ingest any food or water containing those chemicals.

C．The only disadvantage to using chemicals in farming is their potential effect on wildlife.

D．The same crops are grown on organic farms as on farms where chemicals are used.

E．Land cultivated by organic farming methods no longer constitutes a habitat for wildlife.

decade a scientific hunch has turned into a bustling business.

Scientists here say they realized they were no to something when they found that brackish water drilled from underground desert aquifers (含土水层) hundreds of feet deep could be used to raise warm-water fish. The geothermal water, less than one-tenth as saline as sea water, free of pollutants and a toasty 98 degrees on average, proved an ideal match.

"It was not simple to convince people that growing fish in the desert makes sense," said Samuel Appelbaum, a professor and fish biologist at the Jacob Blaustein Institutes for Desert Research at the Sede Boqer campus of Ben-Gurion University of the Negev.

"It is important to stop with the reputation that arid land is nonfertile, useless land," said Professor Appelbaum, who pioneered the concept of desert aquaculture in Israel in the late 1980s. "We should consider arid land where subsurface water exists as land that has great opportunities, especially in food production because of the low level of competition on the land itself and because it gives opportunities to its inhabitants."

The next step in this country, where water is scarce and expensive, was to show farmers that they could later use the water in which the fish are raised to irrigate their crops in a system called double usage. The organic waste produced by the cultured fish makes the water especially useful, because it acts as fertilizer for the crops.

Fields watered by brackish water dot Israel's Negev and Arava Deserts in the south of the country, where they spread out like green blankets against a landscape of sand dunes and rocky outcrops. At Kibbutz Mashabbe Sade in the Negev, the recycled water from the fish ponds is used to irrigate acres of olive and jojoba groves. Elsewhere it is also used for irrigating date palms and alfalfa.

The chain of multiple users for the water is potentially a model that can be copied, especially in arid third world countries where farmers struggle to produce crops, and Israeli scientists have recently been peddling their ideas abroad.

Dry lands cover about 40 percent of the planet, and the people who live on them are often among the poorest in the world. Scientists are working to share the desert aquaculture technology they fine-turned here with Tanzania, India, Australia and China, among others. (Similar methods offish farming are being used in the Sonoran Desert of Arizona.)

"Each farm could ran itself, which is important in the developing world," said Alon Tal, a leading Israeli environmental activist who recently organized a conference on desertification, with the United Nations Convention to Combat Desertification and Ben-Gurion University, that brought policy makers and scientists from 30 countries to Israel.

"A whole village could adopt such a system," Dr. Tal added.

At the conference, Gregoire de Kalbermatten, deputy secretary general of the antidesertification group at the United Nations, said, "We need to learn from the resilience of Israel in developing dry lands."

Israel, long heralded for its agricultural success in the desert through innovative technologies like drip irrigation, has found ways to use low-quality water and what is considered terrible soil to grow produce like sweet cherry tomatoes, people, asparagus and melon, marketing much of it abroad to Europe, especially during winter.

The history of fish-farming in nondesert areas here, mostly in the Galilee region near the sea, dates back to the late 1920s, before Israel was established as a state. At the time, the country was extremely poor and meat was considered a luxury. But fish was a cheap food source, so fish farms were set up on several kibbutzim in the Galilee.

The early Jewish farmers were mostly Eastern Europeans, and Professor

A．fresh water can be drilled from underground desert aquifers

B．the water drilled from the underground desert aquifers is only one-tenth as salty as sea water

C．the water drilled from the underground desert aquifers contains more nutritious elements than fresh water

D．the water drilled from the underground desert aquifers is not as hot as the sea water

Water

The second most important constituent(构成成份) of the biosphere(生物圈) is liquid water. This can only exist in a very narrow range of temperatures, since water freezes at 0℃ and boils at 100℃. Life as we know it would only be possible on the surface of a planet which had temperatures somewhere within this narrow range.

The earth's supply of water probably remains fairly constant in quantity. The total quantity of water is not known very accurately, but it is about enough to cover the surface of the globe to a depth of about two and three-quarter kilometers. Most of it is in the form. of the salt water of the oceans—about 97 per cent. The rest is fresh, but three-quarters of this is in the form. of ice at the Poles and on mountains, and cannot be used by living systems until melted. Of the remaining fraction, which is somewhat less than one per cent of the whole, there is 10—20 times as much stored underground water as there is actually on the surface. There is also a tiny, but extremely important fractions of the water supply which is present as water vapour in the atmosphere.

Water vapour in the atmosphere is the channel through which the whole water circulation(循环) of the biosphere has to pass. Water evaporated(蒸发) from the surface of the oceans, from lakes and rivers and from moist(潮湿的) earth is added to it. From it the water comes out again as rain or snow, falling on either the sea or the land. There is, as might be expected, a more intensive evaporation per unit area over the sea and oceans than over the land, but there is more rainfall over the land than over the oceans, and the balance is restored by the runoff from the land in the form. of rivers.

Liquid water only exists______.

A．in the center of the earth.

B．on the surface of our planet.

C．in a very narrow range of temperatures.

D．in the costal areas of the earth.

the sea. A large part of the country is below sea level. In fact, Holland is also called the "Netherlands," which means "low lands. " Very tall and strong walls, called dykes, have been built to keep out the sea. But in very rough weather the sea may suddenly burst through a dyke, great damage can be caused by floods when this happens. Three large rivers are also part of the problem. These rivers are the Rhine, the Maas and the Scheldt. They flow through Holland into the North Sea. They have cut many passages across the country. At low tide, the rivers flow into the sea as usual. But at high tide the sea can flow into the rivers. This is because the land is so low. The battles against water never end, but they have made Holland a bigger and better country. In order to prevent floods, the engineers take, or reclaim (开垦，改造) land that was under water. The Dutch have been reclaiming land for seven hundred years. Land is usually reclaimed from a passage between two islands. Two dykes are built across the passage, so they block the water between them. Then the engineers dig long canals and pump the water into them. At low tide, the canals empty the water into the sea. Because the land is so low, water from the sea and rivers can rise up through the ground. For this reason, the pumps continue working even when the land has been drained (that is, when the water has been pumped away). The dykes contain gates, and through these the water is pumped out. In many parts of Holland, pumps must be working all the time. If they stopped, there would be very bad floods. A piece of reclaimed land is called a polder (新辟的低地), and Holland has thousands of polders. Some are very large, but others are quite small. There are farms on many of the polders. Corn and other crops grow well on the drained land, and it gives good grass for cattle. Many small towns and villages stand on polders. Even Amsterdams great airport, Schiphol, was built on reclaimed land. This land used to be under the old Lake Haarlem.

Which of the following can be chosen as the best title of this passage？

A．The Dykes in the Netherlands.

B．The Three Large Rivers in Holland.

C．The Fighting Against Water in Holland.

D．The Reclaiming of Land in the Netherlands.