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The work of removing stones never ends because ______ .
A．more stones grow in winter
B．the farmers want to start more and more new farms
C．there are so many stones in the thin soil
D．both A and B
答案
更多“The work of removing stones never ends because ______ .A．more stones grow in winterB．the f”相关的问题
第1题
This passage says that the work of removing stones______.
A．is usually done during the winter
B．was more difficult before machines were used
C．must be done again and again
D．is an interesting job children enjoy doing
第2题
A it is hard to create an airfree environment.
B it is expensive to remove the sulfate from the environment.
C removing the sulfate slows down hydrogen production.
D the algae’s cells work slowly if there is no oxygen in the air.
第3题
请根据以下内容回答1-5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.
Cells in the green leaves of plants work like tiny factories to convert sunlight, carbon dioxide, and water into 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, Maria Ghirardi of the National Renewable Energy Laboratory in Golden, Colo.,
is working with green algae. She's trying to trick them into producing hydrogen 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 airfree environment. It's the oxygen in the air that prevents algae from making hydrogen most
of the time. Working in an airfree 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. ”
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.
第4题
第一篇 Putting Plants to Work
Using the power of the sun is nothing new. People have had solar-powered calculators and buildings with solar panels(太阳能电池板) for decades. But plants are the real experts. They’ve been using sunlight as an energy source for billions of years.
Cells in the green leaves of plants work like tiny factories to convert sunlight, carbon dioxide(二氧化碳), and water into sugars and starches(淀粉), stored energy that the plants can use. This conversion process is called
photosynthesis(光合作用). 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 very small photosynthesis power stations. For example, Maria Ghirardi of the National Renewable Energy Laboratory in Golden. Colo., is working with green algae(水藻). She’s trying to trick them into producing hydrogen 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 airfree environment. It’s the oxygen in the air that prevents algae from making hydrogen most of the time.
Working in an airfree 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(硫酸盐) 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.”
31 How do plants relate to solar energy？
A They have been using it for billions of years.
B They are the real experts in producing it.
C They have been a source of it.
D They have been used to produce it.
第5题
请根据短文内容，回答题。
Putting Plants to Work
Using the power of the sun is nothing new. People have had solar-powered calculators and buildings with solar panels (太阳能电池板) for decades. But plants are the real experts. They&39;ve been using sunlight as an energy source for billions of years.＜br＞
Cells in the green leaves of plants work like tiny factories to convert sunlight, carbon dioxide(二氧化碳), and water into sugars and starches(淀粉 ), stored energy that the plants can use. This conversion process is called photosynthesis (光合作用 ) . Unfortunately, unless you&39;re a plant, it&39;s difficult and expensive to convert sunlight into storable energy. That&39;s why scientists are taking a closer look at exactly how plants do it.＜br＞
Some scientists are trying to get plants, or biological cells that act like plants, to work as very small photosynthesis power stations. For example, Maria Ghirardi of the National Renewable Energy Laboratory in Golden, Colo, is working with green algae (水藻). She&39;s trying to trick them into producing hydrogen 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.＜br＞
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.＜br＞
For example, algae will produce hydrogen in an airfree environment. It&39;s the oxygen in the air that prevents algae from making hydrogen most of the time.＜br＞
Working in an airfree environment, however, is difficult. It&39;s not a practical way to produce cheap energy. But Ghirardi and her colleagues have discovered that by removing a chemical called sulfate (硫酸盐) from the environment that the algae grow in, they will make hydrogen instead of sugars, even when air is present.＜br＞
Unfortunately, removing the sulfate also makes the algae&39;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&39; activity and produce larger quantities of hydrogen.＜br＞
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&39;s a lot of flexibility in how you can use these organisms."＜
How do plants relate to solar energy？ 查看材料
A.They are the real experts in producing it
B.They have been a source of it
C.They have been used to produce it
D.They have been using it for billions of years
第6题
【M1】
第7题
听力原文：M: Hi, Sue.
W: Hello, Jill, how are you？
M: I'm fine. Did you watch the TV special about barnacles last night？
W: No, I missed it. What did you learn about them？
M: They glue themselves to rocks in the ocean, shortly after birth. They also stay in the same place forever.
W: Right, have you ever tried removing one of these things？ It would be easier to chip the rock away than to get the barnacles off.
M: Exactly, and that's why scientists are trying to figure out what the barnacles glue is made of. It's considered one of the strongest adhesives in nature.
W: And it would have the advantage of being able to work on wet surfaces too.
M: Precisely, and because it's natural protein, it probably wouldn't be harmful to people like so many synthetic glues in use today.
W: Think of all the ways in which doctors and dentists could use such a glue to mend broken bones and fasten false teeth.
M: There could be countless uses. Scientists hope to learn soon exactly how the glue is made, so that people can make use of it.
W: That's good news for the general public. I hope it won't take long for the new glue to be put into use.
(23)
A．The reproductive cycle of barnacles.
B．A new source of protein.
C．Types of sea animals.
D．The adhesive quality of barnacles.
第8题
听力原文： Watching movies is a good way to improve your listening: I would stress the usefulness of repetition. So watch a DVD of an English-language film with Chinese subtitles.Then,a week or so later,watch the film again with the subtitles covered up.This time,you will know broadly what the characters are trying to say, which will help your brain link the English words with their meanings.Of course,you can pause and rewind the film if there are certain bits that really puzzle you.
The next step would be to find a way to listen to the soundtrack of the film without watching it.You should know the scenes and the story well by now,so by removing the pictures your brain will really focus on the language spoken.
Before you do any of this,think carefully about what film you want to use to practice your listening.If you want to learn American English,be sure to watch a film set in the USA.If you choose a really well-regarded film,one that has won lots of Academy Awards,for example,you will probably be able to buy the screenplay of the film,which will be very useful to you.
Lastly, choose a film that you are not going to get tired of if you watch it three times!
This is a very satisfying way to practice your listening.You will really feel that you are improving.
What message does the speaker try to convey in this passage？
A．One can improve listening by watching movies.
B．Everybody wants to improve listening nowadays.
C．There is a good way to memorize vocabularies.
D．One needs to work hard to improve English.
第10题
NASA and the Associated Landscape Contractors of America(ALCA)have【C5】______the findings of a 2-year study that【C6】______the common indoor plant may provide a natural way of helping【C7】______"Sick Building Syndrome."
Research【C8】______the use of biological processes as a means of solving environmental problems, both on the【C9】______and in space habitats(栖息地), has been【C10】______out for many years by Dr. Bill Wolverton,【C11】______a senior research scientist at NASA's John C. Stennis Space Center, Bay St. Louis, Miss.
Based on preliminary evaluations of the use of common indoor plants for indoor air purification and revitalization(恢复活力), ALCA【C12】______NASA to fund a study using about a dozen popular varieties of ornamental plants to determine their【C13】______in removing several key pollutants associated with indoor air pollution. NASA research on indoor plants has found that living plants are so【C14】______at absorbing contaminants in the air that some will be launched into【C15】______as part of the biological life support system aboard future orbiting space stations.
【C16】______research is needed, Wolverton says the study has shown that common indoor landscaping plants can remove【C17】______pollutants from the indoor environment. "We feel that future results will provide an even【C18】______argument that common indoor landscaping plants can be a very effective part of a system used to provide pollution【C19】______homes and work places," he【C20】______.
【C1】
A．offices
B．plants
C．ways
D．homes
