[单选题]In a binary plant, the heat of the geothermal water can be converted into _____.
A.the energy to turn a turbine
B.impermeable rock
C.one or two separators
D.turbine operator
E.little or no water
F.hot springs

[单选题]In a binary plant, the heat of the geothermal water can be converted into _____.
A.the energy to turn a turbine
B.impermeable rock
C.one or two separators
D.turbine operator
E.little or no water
F.hot springs

[单选题]Geothermal(地热)Energy 　　1 Since heat naturally moves from hotter regions to cooler ones, the heat from the earth's center flows outwards towards the surface. In this way, it transfers to the next layer of rock. If the temperature is high enough, some of this rock melts and forms magma(岩浆). The magma ascends in its turn towards the earth's surface. It often remains well below the earth's surface, creating vast areas of hot rock. In such regions, there are deep cracks, which allow rainwater to descend underground. Some of the heated rainwater travels back up to the earth's surface where it will appear as a hot spring. However, if this ascending hot water reaches a layer of impermeable(不可渗透的)rock, it remains trapped, forming a geothermal reservoir. If geothermal reservoirs are close enough to the surface, they can be reached by drilling wells. Hot water and steam shoot up the wells naturally, and can be used to produce electricity in geothermal power plants. 　　2.A few geothermal power plants depend on dry-stem reservoirs which produce steam but little or no water. In these cases, the steam is piped up directly to provide the power to spin a turbine generator. The first geothermal power plant, constructed at Lardarello in Italy, was of this type, and is still producing electricity today. 　　3.Most currently operating geothermal power plants are either "flash" steam plants or binary(双重的)plants. Flash plants produce mainly hot water ranging in temperature from 300° to 700°Fahrenheit. This water is passed through one or two separators where released from the pressure of the underground reservoir, it "flashes" or boils into steam Again, the force of this steam provides the energy to spin the turbine and produce electricity. The geothermal water and steam are then reinjected directly back down into the earth to maintain the volume and pressure of the reservoir. Gradually they will be reheated and can then be used again. 　　4.A reservoir with temperatures below 300° Fahrenheit is not hot enough to flash steam but it can still be used to generate electricity in binary fluid. The steam from this is used to power the turbines. As in the flash steam plant, the geothermal water is recycled back into the reservoir. 文章(23~30) Paragraph1_____
A.Dry steam plants
B.Binary plants
C.Origin of geothermal energy
D.Generation of electricity
E.Flash steam plants
F.Recyclable water and steam

[单选题]The plant products have been carefully inspected and are considered to be ( ) from any quarantine pests.
A.out
B.away
C.free
D.far

[不定项选择题]共用题干 “Salty” Rice Plant Boosts Harvests
British scientists are breeding a new generation of rice plants that will be able to grow in soil containing salt water. Their work may enable abandoned farms to become productive once more.
Tim Flowers and Tony Yeo,from Sussex University's School of Biological Sciences,have spent several years researching how crops,such as rice,could be made to grow in water that has become salty.
The pair have recently begun a three-year programme,funded by the Biotechnology and Bio-logical Sciences Research Council,to establish which genes enable some plants to survive salty conditions.The aim is to breed this capability into crops,starting with rice.
It is estimated that each year more than 10m hectares（公顷）of agricultural land are lost because salt gets into the soil and stunts（妨碍生长）plants. The problem is caused by several fac- tors. In the tropics, mangroves（红树林）that create swamps（沼泽）and traditionally formed barriers to sea water have been cut down.In the Mediterranean,a series of droughts have caused the water table to drop,allowing sea water to seep（渗透）in. In Latin America , irrigation often causes problems when water is evaporated（蒸发）by the heat,leaving salt deposits behind.
Excess salt then enters the plants and prevents them functioning normally.Heavy concentra-tions of minerals in the plants stop them drawing up the water they need to survive.
To overcome these problems,Flowers and Yeo decided to breed rice plants that take in very little salt and store what they do absorb in cells that do not affect the plants' growth.They have started to breed these characteristics into a new rice crop,but it will take about eight harvests before the resulting seeds are ready to be considered for commercial use.
Once the characteristics for surviving salty soil are known,Flowers and Yeo will try to breed the appropriate genes into all manners of crops and plants.Land that has been abandoned to na-ture will then be able to bloom again,providing much needed food in the poorer countries of the world. The attitude of the author towards the research project is_______.
A.positive
B.negative
C.suspicious
D.indifferent

[不定项选择题]共用题干 第一篇

Plant Gas

Scientists have been studying natural sources of methane（甲烷，沼气）for decades but hadn't regarded plants as a producer, notes Frank Keppler, a geochemist（地球化学家）at the Max Planck Institute for Nuclear Physics in Heldelberg,Germany. Now Keppler and his colleagues find that plants,from grasses to trees,may also be sources of the greenhouse gas.This is really surprising, because most scientists assumed that methane production requires an oxygen-free environment.
Previously,researchers had thought that it was impossible for plants to make significant amounts of the gas. They had assumed that microbes（微生物）need to be in environments without oxygen to produce methane.Methane is a greenhouse gas, like carbon dioxide.Gases such as methane and carbon dioxide trap heat in Earth's atmosphere and contribute to global warming.
In its experiments, Keppler's team used sealed chambers（室，房间；腔）that contained the same concentration of oxygen that Earth's atmosphere has.They measured the amounts of methane that were released by both living plants and dried plant material,such as fallen leaves.
With the dried plants,the researchers took measurement at temperatures ranging from 30 degrees Celsius to 70 degrees C.At 30 degrees C.,they found,a gram of dried plant material released up to 3 nanograms（微克）of methane per hour(One nanogram is a millionth of a gram). With every 10-degree rise in temperature,the amount of methane released each hour roughly doubled.
Living plants growing at their normal temperatures released as much as 370 nanograms of methane per gram of plant tissue per hour. Methane emissions tripled when living and dead plant was exposed to sunlight.
Because there was plenty of oxygen available,it's unlikely that the types of bacteria(bacterium的复数，细菌）that normally make methane were involved. Experiments on plants that were grown in water rather than soil also resulted in methane emissions.That's another strong sign that the gas came from the plants and not soil microbes.
The new finding is an"interesting observation,"says Jennifer Y. King,a biogeochemist（生物地球化学家）at the University of Minnesota in St. Paul. Because some types of soil microbes consume methane,they may prevent plant-produced methane from reaching the atmosphere.Field tests will be needed to assess the plant's influence,she notes. What is the beneficial point of some microbes consuming plant-produced methane?
A.Methane becomes less poisonous.
B.Methane is turned into a fertilizer.
C.Less methane reaches the atmosphere.
D.Air becomes cleaner.