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Small green plants are very important to dry places because______.
A．they don't let the sun make the earth even drier
B．they don't let the wind blow the earth away
C．they hold water
D．all of the above
答案
更多“Small green plants are very important to dry places because______.A．they don't let the sun”相关的问题
第1题
Small plants like grasses and herbs are grown widely on intensive green roofs.
A Right B Wrong C Not mentioned
第2题
Small plants like grasses and herbs are grown widely on intensive green roofs.
A．Right
B．Wrong
C．Not mentioned
第3题
Small green plants are very important to dry places because ______.
A．they don't let the sun make the earth even drier
B．they don't let the wind blow the earth away
C．they hold water
D．all of the above
第4题
Some places on the earth don't get very much rain. But they still don't become deserts. This is because some green plants are growing there. Small green plants and grass are very important to dry places. Plants don't let the hot sun make the earth even drier. Plants don't let the wind blow the dirt(土)away. When a little bit of rain falls, the plants hold the water. Without plants, the land can become a desert much more easily.
Deserts ______.
A．get very little rain
B．never have any plants or animals in them
C．can all be turned into good land before long
D．both A and C
第5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6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7题
What is the main idea of this passage？
A．How green plants make food.
B．How green plants make sugar.
C．How green plants get their energy.
D．How green plants change sugar into starc
第8题
A．When there are two lines of plants in each windbreak.
B．When there is space left for some wind to go through.
C．When they are planted around crops.
D．When local green trees are planted in windbreaks.
第9题
A．Chlorosis on leaves
B．Change in leaf pigmentation to a dark shade of green
C．Short, stunted appearance of stems
D．Reddish pigmentation on the leaves or stem
