单选题
Listening 6 "Botany Class"
单选题
What is this discussion mainly about?
A. Growing plants without soil
B. Mixing nutrients in water
C. Identifying chemicals in soil
D. Solving problems in the water
A. Growing plants without soil
B. Mixing nutrients in water
C. Identifying chemicals in soil
D. Solving problems in the water
【正确答案】
A
【答案解析】[解析] 29-34
[Narrator] Listen to part of a discussion in a botany class. The professor is talking about hydroponics.
[Professor]
Although the recent interest in hydroponics may lead you to believe that it's a relatively new idea, the Q29
process probably originated in ancient times. In fact, the famous Hanging Gardens of Babylon may well
have been one of the first successful attempts to grow plants in water, that is, hydroponically. Early agriculture
in Pakistan and India as well as other areas throughout the Middle East included water crops,
and we also have evidence that the Egyptians were growing plants in water along the Nile... and that
was without soil. Asia and the South Pacific were prime locations for early hydroponic gardens. And, in
the Western Hemisphere, we know that the Aztecs had developed an advanced system of water agriculture
along the marshlands of Lake Tenochtitlan in the Central Valley of Mexico because, when the
Spanish arrived, they made drawings in their journals of "floating islands of trees and vegetation," in
other words, hydroponic agriculture.
Okay, well, this isn't a history class. It's a botany class. But I think it's important when we're talking Q30
about scientific discoveries that we understand how science works. Sometimes we're rediscovering and
refining methods that have been used for a very long time, and that's certainly the case of hydroponics.
Through the years, it's been called nutriculture, chemiculture, acquiculture, soilless culture, but the
current term is hydroponics, and that encompasses the modern science of growing plants without soil
by using an inert medium such as sand, peat, gravel, or... or even sawdust or Styrofoam. Of course,
you have to add a solution of nutrients.
Clearly, good soil has the nutrients necessary for plant growth, but when plants are grown without
soil, all the nutrients must be provided in another way. So, why do you think that we would go to all of
this additional effort to replace soil?
[Student 1]
Well, I think the book mentioned something about keeping the growing medium more sterile.
[Professor]
Umhum. Soil-borne diseases and pests and even weeds can be... virtually eliminated... by using a
soil alternative.
[Student 1]
So I was thinking probably you wouldn't require as much labor, to get rid of the pests and weeds.
[Professor]
Good thought. Now tell me what you know about fertilizer and water.
[Student 2]
Oh, right. Less fertilizer and water are required per plant since they're constantly reused, and aren't the
results more uniform because of the highly controlled conditions?
[Professor]
Right on both counts. But probably the most important advantage is the ability to cultivate a larger number Q31
of plants in a limited space..... Where would this be important do you think?
[Student 1]
Well, small or isolated environments or very arid climates with limited fresh water supplies probably.
[Student 2]
Or regions with poor soils, for instance, in developing countries where the weather conditions aren't Q32
dependable ands., and famine might... could happen.
[Student 1] Or the area may have a dense population.
[Professor] So hydroponics is limited to developing regions then.
Student 3:
I'm not sum about that. Even in highly industrialized nations, populations are growing and... and isn't
the total acreage in cultivation dropping to accommodate the expansion of urban areas?
[Professor]
Well stated. As agricultural land is sold for development, hydroponics has become a viable option for,
well, for almost every country in the world.
Now earlier, I said that we're often rediscovering ancient methods in science, but we're also adapting
them by using improvements from other scientific research. In the case of hydroponics, there are
probably two modern discoveries that have supported progress in hydroponics. Okay. First, the development
of plastics... that allowed growers to abandon the old concrete beds, which were costly to construct
and problematic because... because they leached into the nutrient solution. But, plastic beds are
cheap, they're light, and sterile... an ideal replacement for concrete. And many of the greenhouses
themselves are even built of plastic panels. Okay. The other important advancement is the knowledge
we've accumulated about plant nutrition. Of course, like I said, good soil has the nutrients necessary for
plant growth, but when plants are grown without soil, all the nutrients must be provided in another way.
And now we have a much better idea of what we need to use in the solution to obtain the best results.
So... all of that said, let's talk about the lab experiment that we've set up here. This solution contains
potassium nitrate, ammonium sulfate, magnesium sulfate, monocalcium phosphate, and calcium
sulfate. Don't try to write down all of that now. You can refer to your lab workbook for the list of substances Q33
and the proportions needed for proper plant growth.
[Narrator] Listen to part of a discussion in a botany class. The professor is talking about hydroponics.
[Professor]
Although the recent interest in hydroponics may lead you to believe that it's a relatively new idea, the Q29
process probably originated in ancient times. In fact, the famous Hanging Gardens of Babylon may well
have been one of the first successful attempts to grow plants in water, that is, hydroponically. Early agriculture
in Pakistan and India as well as other areas throughout the Middle East included water crops,
and we also have evidence that the Egyptians were growing plants in water along the Nile... and that
was without soil. Asia and the South Pacific were prime locations for early hydroponic gardens. And, in
the Western Hemisphere, we know that the Aztecs had developed an advanced system of water agriculture
along the marshlands of Lake Tenochtitlan in the Central Valley of Mexico because, when the
Spanish arrived, they made drawings in their journals of "floating islands of trees and vegetation," in
other words, hydroponic agriculture.
Okay, well, this isn't a history class. It's a botany class. But I think it's important when we're talking Q30
about scientific discoveries that we understand how science works. Sometimes we're rediscovering and
refining methods that have been used for a very long time, and that's certainly the case of hydroponics.
Through the years, it's been called nutriculture, chemiculture, acquiculture, soilless culture, but the
current term is hydroponics, and that encompasses the modern science of growing plants without soil
by using an inert medium such as sand, peat, gravel, or... or even sawdust or Styrofoam. Of course,
you have to add a solution of nutrients.
Clearly, good soil has the nutrients necessary for plant growth, but when plants are grown without
soil, all the nutrients must be provided in another way. So, why do you think that we would go to all of
this additional effort to replace soil?
[Student 1]
Well, I think the book mentioned something about keeping the growing medium more sterile.
[Professor]
Umhum. Soil-borne diseases and pests and even weeds can be... virtually eliminated... by using a
soil alternative.
[Student 1]
So I was thinking probably you wouldn't require as much labor, to get rid of the pests and weeds.
[Professor]
Good thought. Now tell me what you know about fertilizer and water.
[Student 2]
Oh, right. Less fertilizer and water are required per plant since they're constantly reused, and aren't the
results more uniform because of the highly controlled conditions?
[Professor]
Right on both counts. But probably the most important advantage is the ability to cultivate a larger number Q31
of plants in a limited space..... Where would this be important do you think?
[Student 1]
Well, small or isolated environments or very arid climates with limited fresh water supplies probably.
[Student 2]
Or regions with poor soils, for instance, in developing countries where the weather conditions aren't Q32
dependable ands., and famine might... could happen.
[Student 1] Or the area may have a dense population.
[Professor] So hydroponics is limited to developing regions then.
Student 3:
I'm not sum about that. Even in highly industrialized nations, populations are growing and... and isn't
the total acreage in cultivation dropping to accommodate the expansion of urban areas?
[Professor]
Well stated. As agricultural land is sold for development, hydroponics has become a viable option for,
well, for almost every country in the world.
Now earlier, I said that we're often rediscovering ancient methods in science, but we're also adapting
them by using improvements from other scientific research. In the case of hydroponics, there are
probably two modern discoveries that have supported progress in hydroponics. Okay. First, the development
of plastics... that allowed growers to abandon the old concrete beds, which were costly to construct
and problematic because... because they leached into the nutrient solution. But, plastic beds are
cheap, they're light, and sterile... an ideal replacement for concrete. And many of the greenhouses
themselves are even built of plastic panels. Okay. The other important advancement is the knowledge
we've accumulated about plant nutrition. Of course, like I said, good soil has the nutrients necessary for
plant growth, but when plants are grown without soil, all the nutrients must be provided in another way.
And now we have a much better idea of what we need to use in the solution to obtain the best results.
So... all of that said, let's talk about the lab experiment that we've set up here. This solution contains
potassium nitrate, ammonium sulfate, magnesium sulfate, monocalcium phosphate, and calcium
sulfate. Don't try to write down all of that now. You can refer to your lab workbook for the list of substances Q33
and the proportions needed for proper plant growth.
单选题
Why does the professor talk about the history of hydroponics?
A. She wants to put the modern method in historical context.
B. She is trying to prove that hydroponics is a new idea.
C. She is following the information in the textbook very closely.
D. She digressed from the subject for a long time.
A. She wants to put the modern method in historical context.
B. She is trying to prove that hydroponics is a new idea.
C. She is following the information in the textbook very closely.
D. She digressed from the subject for a long time.
【正确答案】
A
【答案解析】[解析]
Why does the professor talk about the history of hydroponics?
She wants to put the modern method in historical context.
Why does the professor talk about the history of hydroponics?
She wants to put the modern method in historical context.
单选题
According to the professor, what is the greatest advantage of hydroponics?
A. The plants are less likely to develop soil-borne diseases.
B. The cultivation requires much less labor than traditional methods.
C. The water can be recycled in a hydroponic environment.
D. Less space is needed to produce a large number of plants.
A. The plants are less likely to develop soil-borne diseases.
B. The cultivation requires much less labor than traditional methods.
C. The water can be recycled in a hydroponic environment.
D. Less space is needed to produce a large number of plants.
【正确答案】
D
【答案解析】[解析]
According to the professor, what is the greatest advantage of hydroponics?
Less space is needed to produce a large number of plants.
According to the professor, what is the greatest advantage of hydroponics?
Less space is needed to produce a large number of plants.
单选题
Why does the professor say this:
A. She is making a statement to generate further discussion.
B. She is drawing a conclusion to end the point about soil.
C. She is answering the question that was posed about regions.
D. She is trying to understand what the student just said.
A. She is making a statement to generate further discussion.
B. She is drawing a conclusion to end the point about soil.
C. She is answering the question that was posed about regions.
D. She is trying to understand what the student just said.
【正确答案】
A
【答案解析】[解析]
Listen again to part of the discussion and then answer the following question.
"Or regions with poor soils, for instance, in developing countries where the weather conditions aren't dependable and... and famine might... could happen."
"Or the area may have a dense population."
"So hydroponics is limited to developing regions then."
"I'm not sure about that."
Why does the professor say this:
"So hydroponics is limited to developing regions then."
Her tone is not conclusive. She is making a statement to generate further discussion.
Listen again to part of the discussion and then answer the following question.
"Or regions with poor soils, for instance, in developing countries where the weather conditions aren't dependable and... and famine might... could happen."
"Or the area may have a dense population."
"So hydroponics is limited to developing regions then."
"I'm not sure about that."
Why does the professor say this:
"So hydroponics is limited to developing regions then."
Her tone is not conclusive. She is making a statement to generate further discussion.
单选题
Why does the professor suggest that the students refer to their lab workbook?
A. To see the diagram of the experiment
B. To read more about plant growth
C. To find a list of important plant nutrients
D. To locate the instructions for building a tank
A. To see the diagram of the experiment
B. To read more about plant growth
C. To find a list of important plant nutrients
D. To locate the instructions for building a tank
【正确答案】
C
【答案解析】[解析]
Why does the professor suggest that the students refer to their lab workbook?
To find a list of important plant nutrients
Why does the professor suggest that the students refer to their lab workbook?
To find a list of important plant nutrients
多选题
According to the professor, why are roots important to plants?
Click on 2 answer choices.
A. To absorb water and nutrients
B. To take in enough oxygen
C. To suspend the plants in the solution
D. To filter out toxic substances
Click on 2 answer choices.
A. To absorb water and nutrients
B. To take in enough oxygen
C. To suspend the plants in the solution
D. To filter out toxic substances
【正确答案】
【答案解析】[解析]
According to the professor, why are roots important to plants?
To absorb water and nutrients
To suspend the plants in the solution
According to the professor, why are roots important to plants?
To absorb water and nutrients
To suspend the plants in the solution