单选题
单选题
Putting Plants to Work
Using the power of the sun is nothing new. People have had solar-powered calculators and buildings with solar panels for decades. But plants are the real experts: They’ve been using sunlight as an energy source for billions of years.
Ceils in the green leaves of plants work like tiny factories to convert sunlight, carbon dioxide, and water into1 sugars and starches, stored energy that the plants can use. This conversion process is called photosynthesis. Unfortunately, unless you’re a plant, it’s difficult and expensive to convert sunlight into storable energy. That’s why scientists are taking a closer look at exactly how plants do it.
Some scientists are trying to get plants, or biological cells that act like plants, to work as miniature photosynthetic power stations. For example, Mafia Ghirardi of the National Renewable Energy Laboratory in Golden, Colo.2, is working with green algae3. She’s trying to trick them into producing hydrogen4 instead of sugars when they perform photosynthesis. Once the researchers can get the algae working efficiently, the hydrogen that they produce could be used to power fuel cells in cars or to generate electricity.
The algae are grown in narrow-necked glass bottles to produce hydrogen in the lab. During photosynthesis, plants normally make sugars or starches. “But under certain conditions, a lot of algae are able to use the sunlight energy not to store starch, but to make hydrogen,” Ghirardi says. For example, algae will produce hydrogen in an air free environment. It’s the oxygen in the air that prevents algae from making hydrogen most of the time.
Working in an air free environment, however, is difficult. It’s not a practical way to produce cheap energy. But Ghirardi and her colleagues have discovered that by removing a chemical called sulfate from the environment that the algae grow in, they will make hydrogen instead of sugars, even when air is present.
Unfortunately, removing the sulfate also makes the algae’s cells work very slowly, and not much hydrogen is produced. Still, the researchers see this as a first step in their goal to produce hydrogen efficiently from algae. With more work, they may be able to speed the cells" activity and produce larger quantities of hydrogen.
The researchers hope that algae will one day be an easy-to-use fuel source. The organisms are cheap to get and to feed, Ghirardi says, and they can grow almost anywhere: “You can grow them in a reactor, in a pond. You can grow them in the ocean. There’s a lot of flexibility in how you can use these organisms.”
词汇:
panel /5pAnl/ n.嵌板，发热板，仪器板
starch /stB:tF/ n. 淀粉
miniature /5minjEtFE/ adj.口巧．微型的
sulfate /5sQlfeit/ n. 硫酸盐，硫酸酯
carbon dioxide 二氧化碳
photosynthesis /7fEutEu5sinWEsis/ n. 光合作用
algae /5AldVi:/ n. 水藻，海藻
注释:
1. convert … into…：将……转换为 ……
2. Colo.：Colorado，（美国科罗拉多州）的缩写形式
3. Green algae: 绿藻
4.trick them into producing hydrogen: 想方设法使它们产生氢。 trick作为动词，有 “欺骗、哄骗 ”的意思，但是在这里的意思是 “设法”或“采取措施 ”。What does the writer say about plants concerning solar energy?
A:Plants are "the real experts in producing solar energy. B:Plants have been used to produce solar energy. C:Plants have been using solar energy for billions of years. D:Plants have been a source of solar energy.
能值（Energy）
Quantity of energy contained in the atmosphere is ______.
A:smaller than that in coal alone B:smaller than that either in oil or in gas that we have on Earth C:greater than that in coal, oil and gas on Earth combined D:greater than that in coal, oil and gas on Earth, respectively
How can we get rid of garbage Do we have enough energy sources to meet our future energy needs
These are two important questions that many people are asking today. Some people think that man might be able to solve both problems at the same time. They suggest using garbage as an energy source, and at the some time it can save the land to hold garbage.
For a long time, people buried garbage or dumped(倾倒) it on empty land. Now, empty land is scarce. But more and more garbage is produced each year. However, garbage can be a good fuel to use. The things in garbage do not look like coal, petroleum, or natural gas; but they are chemically similar to these fossil(化石) fuels. As we use up our fossil fuel supplies, we might be able to use garbage as an energy source.
Burning garbage is not a new idea. Some cities in Europe and the United States have been burning garbage for years. (78) The heat that is produced by burning garbage is used to boil water. The steam that is produced is used to make electricity or to heat nearby buildings. In Paris, France, some power plants bum almost 2 million metric tons of the cities garbage each year. The amount of energy produced is about the same as would be produced by burning almost a half million barrels of oil.
Our fossil fuel supplies are limited. (79) Burning garbage might be one kind of energy source that we can use to help meet our energy needs. This method could also reduce the amount of garbage piling up on the earth.
What two problems can man solve by burning garbage
A:The shortage of energy and air pollution. B:The shortage of energy and the land to hold garbage. C:Air pollution and the shortage of fossil fuel. D:Air pollution and the shortage of land to hold garbag
Passage 3
| How can we get rid of garbage Do we
have enough energy sources to meet our future energy needs These are two important questions that many people are asking today. Some people think that man might be able to solve both problems at the same time. They suggest using garbage as an energy source, and at the some time it can save the land to hold garbage. For a long time, people buried garbage or dumped(倾倒) it on empty land. Now, empty land is scarce. But more and more garbage is produced each year. However, garbage can be a good fuel to use. The things in garbage do not look like coal, petroleum, or natural gas; but they are chemically similar to these fossil(化石) fuels. As we use up our fossil fuel supplies, we might be able to use garbage as an energy source. Burning garbage is not a new idea. Some cities in Europe and the United States have been burning garbage for years. (78) The heat that is produced by burning garbage is used to boil water. The steam that is produced is used to make electricity or to heat nearby buildings. In Paris, France, some power plants bum almost 2 million metric tons of the cities garbage each year. The amount of energy produced is about the same as would be produced by burning almost a half million barrels of oil. Our fossil fuel supplies are limited. (79) Burning garbage might be one kind of energy source that we can use to help meet our energy needs. This method could also reduce the amount of garbage piling up on the earth. |
A:The shortage of energy and air pollution. B:The shortage of energy and the land to hold garbage. C:Air pollution and the shortage of fossil fuel. D:Air pollution and the shortage of land to hold garbage.
Chemical energy is generated ______.
? ?阅读下面的短文，文中有15处空白，每处空白给出了4个选项，请根据短文的内容从4个选项中选择1个最佳答案。
A:phone B:water C:food D:energy
Less Is More It sounds all wrong--drilling holes in a piece of wood to make it more resistant to knocks．But it works because the energy from the blow gets distributed throughout the wood rather than focusing on one weak spot．The discovery should lead to more effective and lighter packaging materials. Carpenters have known ________(51)centuries that some woods are tougher than others．Hickory(山核桃木)，for example，was turned into axe handles and cartwheel spokes(轮辐)because it Can absorb shocks without breaking．White oak，for example，is much more easily damaged，_________ (52)it is almost as dense．Julian Vincent at Bathe University and his team were convinced the wood’s internal structure could explain the differences． Many trees have tubular(管的)vessels that run _________ (53)the trunk and carry water to the leaves．In oak they are large，and arranged in narrow bands，but in hickory they are smaller，and more evenly distributed．The researchers _________ (54)this layout might distribute a blow’s energy throughout the wood．soaking up a bigger hit．To test the idea，they drilled holes 0.65 millimetres across into a block of spruce(云杉)，a wood with _________ (55)vessels，and found that _________ (56)withstood a harder knock．_________ (57)when there were more than about 30 holes per square centimetre did the wood’s performance drop off． A uniform substance doesn’t cope well with knocks because only a small proportion of the material is actually _________ (58)．All the energy from the blow goes towards breaking the material in one or two places，but often the pieces left _________ (59)are pristine(未经破坏的)． But instead of the energy being concentrated in one place，the holes provide many weak spots that all absorb energy as they break，says Vincent．“You are controlling the places_________ (60)the wood breaks，and it can then absorb more _________ (61)，more safely．”The researchers believe the principle could be applied to any material- _________ (62)example．to manufacture lighter and more protective packaging．It could _________ (63)be used in Car bumpers，crash barriers and armour for military vehicles，says Ulrike Wegst， _________ (64)the Max Plank Institute for Mental Research in Stuttgart．But she emphasizes that you _________ (65)to design the substance with the direction of force in mind．“The direction of loading is crucial，”she says．
A:water B:air C:energy D:safety
Which of the following statements concerning energy is correct?
A:Energy can be created or destroyed B:Energy may not be transformed C:The total quantity of energy in the universe is always the same D:None of the above
The energy associated with molecules is known as _____.
A:kinetic energy B:potential energy C:mechanical energy D:thermal energy
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