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Which of the following statements is true concerning carbon dioxide when used as a fire extinguishing agent?（）
A . Carbon dioxide is corrosive when exposed to fire
B . Carbon dioxide should be applied slowly to a large engine room fire
C . Its total cooling effect is far greater than water
D . Its smothering effect is excellent for class B fire
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When using carbon dioxide to fight a fire on a bulkhead，the CO2 should be applied（）.
A . first to the bottom of the flaming area，sweeping from side to side，and following the flames upward
B . in a circular motion from the middle of the bulkhead outward
C . to the top of the flaming area，sweeping from side to side，and working toward the bottom
D . in an up-and-down motion from one side of the bulkhead to the other
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On a ship，a fixed carbon dioxide or other approved system must be installed（）.
A . where oil or chemical drums are stored
B . in all battery storage locations
C . in paint lockers
D . in all of the above locatio
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One of the disadvantages of using carbon dioxide to extinguish a fire in an enclosed space is （）.
A . the "snow" which is sometimes discharged along with the gas is toxic
B . prolonged exposure to high concentrations of C0
gas causes suffocation
C . rapid dissipation of the C0
vapor
D . the C0
gas is lighter than air and a large amount is required to extinguisha fire near the deck
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A carbon dioxide fire extinguisher has been partially discharged, and should be immediately （）.
A . tagged and restowed properly in its rack
B . weighed and the charge loss recorded
C . given to the chief engineer for recharging
D . tagged "empty" and stowed separately from charged extinguisher
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An advantage of a dry chemical over a carbon dioxide fire extinguisher is its（）.
A . greater range
B . effectiveness on all types of fires
C . cleanliness
D . All of the above
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Carbon dioxide的中文含义是（）。
A . 碳氢化合物
B . 碳氧化合物
C . 一氧化碳
D . 二氧化碳
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Carbon dioxide flooding system is used for extinguishing fires because it reduces the concentration of oxygen in the air to（）.
A . flashing point
B . combustion point
C . auto-ignition point
D . lower explosive limit
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Carbon dioxide as a fire fighting agent has which advantage over other agents? （）
A . It causes minimal damage
B . It is safer for personnel
C . It is cheaper
D . It is most effective on a per unit basi
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An advantage of an ABC dry chemical over a carbon dioxide extinguisher is（）.
A . lack of toxicity
B . the multipurpose extinguishing ability
C . burn-back protection
D . cooling ability
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The discharge from a carbon dioxide fire extinguisher should be directed（）.
A . at the base of the flames
B . at the center of the flames
C . to the lee side of the flames
D . over the tops of the flame
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Large volumes of carbon dioxide are safe and effective for fighting fires in enclosed spaces，such as in a pumproom，provided that the（）.
A . persons in the space wear gas masks
B . persons in the space wear damp cloths over their mouths and nostrils
C . ventilation system is secured and all persons leave the space
D . ventilation system is kept operating
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An advantage of a dry chemical over a carbon dioxide fire extinguish is its（）.
A . greater range
B . effective on all types of fires
C . cleanliness
D . All of the above
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Carbon dioxide as a fire fighting agent has which advantage over other agents?（）.
A . It causes minimal damage
B . It is safe for personnel
C . It is cheaper
D . It is most effective on a per unit basi
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As compared to carbon dioxide,dry chemical has which advantage?（）.
A . Cleaner
B . Effective
C . Greater range
D . More cooling effect
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Fire in an engine compartment is best extinguished with carbon dioxide gas (CO2) and by（）.
A . completely closing the compartment
B . closing the compartment except for the ventilators
C . leaving the compartment open to the air
D . increasing the air flow to the compartment by blower
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What is NOT a characteristic of carbon dioxide fire-extinguishing agents?（）
A . Effective even if ventilation is not shut down
B . Will not deteriorate in storage
C . Non-corrosive
D . Effective on electrical equipment
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For which of the listed classes of fire combinations would carbon dioxide be most suitable as the extinguishing agent （）.
A . Class "A" and class "B"
B . Class "B" and class "C"
C . Class "A" and class " C"
D . Class "C", class "D", and class "E"
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Which extinguishing agent is recommended in the Chemical Data Guide for use on a carbon disulfide fire?（）
A . Alcohol foam
B . Dry chemical
C . Chemical foam
D . Water fog
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A rise in carbon dioxide concentration in the blood cause（ ）
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A squeeze-grip type carbon dioxide portable fire extinguisher has been partially discharged.It should be ______.
A.replaced in its proper location if weight loss is no more than 15%
B.replaced in its proper location if weight loss is no more than 25%
C.labeled empty and recharged as soon as possible
D.labeled empty and replaced in its proper location regardless of weight
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Why does the author discuss carbon dioxide's relationship to global warming in Paragraph 5？
A．To illustrate methane's molecular structure.
B．To show the link between global warming and smog.
C．To suggest that fossil fuels should not be burned.
D．To elaborate on a benefit of natural gas's cleanliness.
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Scientists have long believed one way to stop the Earth’s atmosphere from warming is by planting more trees. The idea is that more trees will take in or absorb some of the carbon dioxide in the atmosphere. Carbon dioxide is a gas released by cars, factories and other human activities. The gas traps heat in the Earth’s atmosphere, which warms the planet. However, two new studies have found that trees may not be as helpful in reducing carbon dioxide as had been thought.
The first study was done at Duke University in Durham, North Carolina. Researchers pumped extra carbon dioxide into a test area where pine trees were growing. The trees grew thirty-four percent faster during the first three years. However, in time, the trees slowed to about their normal growth rate. The scientists say this is because trees need other nutrients, such as nitrogen.
In the second study, researchers from Duke and Bowdoin College in Brunswick, Maine examined the soil around trees. They discovered that as the leaves broke down into the soil, all the carbon was not trapped in the soil. Much of it was released into the atmosphere as carbon dioxide.
The findings of the two studies were published last month in Nature magazine. They suggest there is limited value in planting trees to reduce the carbon dioxide pollution in the atmosphere.
Forest planting has been a part of negotiations on a world agreement to reduce greenhouse gases that scientists believe cause global warming. The United States, Canada, Japan and some other industrial countries have supported the idea. But this new research suggests the idea is not as effective as environmental activists had thought. Scientist Ram Oren of Duke University led the study on tree growth. He says that earlier estimates on the ability of forests to absorb carbon dioxide were overly hopeful.
Some scientists not involved in the studies say the research provides some of the first evidence on how trees react to carbon dioxide. Other scientists say the research disputes a belief among some coal and power companies. The companies say that rising levels of carbon dioxide in the atmosphere will not create harmful global warming. Instead, they say it will increase forests and other plants.
What is the purpose of this passage？
A．Introduce some new ideas about the relationship between trees and carbon dioxide.
B．Introduce recent condition of global industrial pollution.
C．Call on people to plant more trees to reduce greenhouse gases.
D．Point out that power companies should be responsible for the rising levels of carbon dioxide.
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Green plants take in carbon dioxide and give off oxygen in a food-making process called photosynthesis．
A.donate
B.check
C.withhold
D.release
