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Wood will burst into flames at 300 degrees Fahrenheit.A．YB．NC．NG

Wood will burst into flames at 300 degrees Fahrenheit.

A．Y

B．N

C．NG

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发布时间：2020-11-14

更多“Wood will burst into flames at 300 degrees Fahrenheit.A．YB．NC．NG”相关的问题

第1题

Pat O’Burke was a poor Irishman with a large family, and one morning, waking up very ea

rly from cold and hunger, he decided to go shooting in a wood near his cottage(小屋，村舍). The wood belonged to Lord Northwood, a rich gentleman, and Pat had no right to go there, but in it there were swarms of rabbits and flocks of birds that were good to eat, and Pat determined to take the risk. Suddenly he saw the owner, with a group of friends, coming towards him in the wood. There was a look of anger on Lord Northwood’s face as he caught sight of the gun in Pat’s hands. Pat’s heart sank with fear, but he saw there was no hope of escape, so he walked boldly up to the company and said to Lord Northwood, “Good morning, sir, and what has brought you out so early this morning？” Lord Northwood, rather surprised, said he and his friends were taking a little exercise to get an appetite for their breakfast. Then, looking at Pat with suspicion, he said, “But why are you out so early in the morning？” “Well, sir,” said Pat, “I just came out to see if I could get a breakfast for my appetite.” The whole crowd burst into laughter at Pat’s ready wit, and with a smile Lord Northwood walked on, leaving Pat to try his luck with the rabbits.

(1).This is a story about().

A、a rich man who owned a big wood.

B、 a poor Irishman who lived all by himself.

C、 a clever man who tried to get something to eat for his breakfast.

D、 an Irish hunter with a large family.

(2). There was a look of anger on Lord Northwood’s face. Why？()

A、 He was not expecting Pat at this early hour.

B、 He knew Pat was coming for shooting.

C、 He didn’t like the poor Irishman at all.

D、 Pat had not told him he would come.

(3). Why was Lord Northwood surprised？()

A、 He had not expected such a bold question from Pat.

B、 He wondered why Pat didn’t run away.

C、 Pat wasn’t afraid of him.

D、 Pat had a gun in his hands.

(4).Pat’s _______ made the whole crowd burst into laughter.()

A、 funny looks

B、 interesting remarks

C、 quick and witty response

D、 promise to leave right away

(5).It was because of his _________ that Pat was left to try his luck.

A、 boldness

B、 calmness

C、 quickness of mind

D、 obedience (服从, 顺从)

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第2题

WildfiresIn just seconds, a spark or even the sun's heat alone sets off an extremely large

Wildfires

In just seconds, a spark or even the sun's heat alone sets off an extremely large fire. The wildfire quickly spreads, consuming the thick, dried-out plants and almost everything else in its path. What was once a forest becomes a virtual powder keg of untapped fuel. In a seemingly instantaneous burst, the wildfire overtakes thousands of acres of surrounding land, threatening the homes and lives of many in the vicinity.

Fire Starters

On a hot summer day, when drought conditions peak, something as small as a spark from a train car's wheel striking the track can ignite a raging wildfire. Sometimes, fires occur naturally, ignited by heat from the sun or a lightning strike. However, the majority of Wildfires are the result of human carelessness.

Common causes for wildfires include:

Arson

Campfires

Discarding lit cigarettes

Improperly burning debris

Playing with matches or fireworks

Prescribed fires

Everything has a temperature at which it will burst into flames. This temperature is called a material's flash point. Wood's flash point is 572 degrees Fahrenheit(300 ℃). When wood is heated to this temperature, it releases hydrocarbon gases that mix with oxygen in the air, combust and create fire.

There are three components needed for ignition and combustion to occur. A fire requires fuel to burn, air to supply oxygen, and a heat source to bring the fuel Up to ignition temperature. Heat, oxygen and fuel form. the fire triangle. Firefighters often talk about the fire triangle when they are trying to put out a blaze. The idea is that if they can take away any one of the pillars of the triangle, they can control and ultimately extinguish the fire.

After combustion occurs and a fire begins to burn, there are several factors that determine how the fire spreads. These three factors include fuel, weather and topography. Depending on these factors, a fire can quickly fizzle or turn into a raging blaze that scorches thousands of acres.

Fueling the Flames

Wildfires spread based on the type and quantity of fuel that surrounds it. Fuel can include everything from trees, underbrush and dry grassy fields to homes. The amount of flammable material that surrounds a fire is referred to as the fuel load. Fuel load is measured by the amount of available fuel per unit area, usually tons per acre.

A small fuel load will cause a fire to burn and spread slowly, with a low intensity. If there is a lot of fuel, the fire will burn more intensely, causing it to spread faster. The faster it heats up the material around it, the faster those materials can ignite. The dryness of the fuel can also affect the behavior. of the fire. When the fuel is very dry, it is consumed much faster and creates a fire that is much more difficult to contain.

Here are the basic fuel characteristics that decide how it affects a fire:

Size and shape

Arrangement

Moisture content

Small fuel materials, also called flashy fuels, such as dry grass, pine needles, dry leaves, twigs and other dead brush, burn faster than large logs or stumps(this is why you start a fire with kindling rather than logs). On a chemical level, different fuel materials take longer to ignite than others. But in a wildfire, where most of the fuel is made of the same sort of material, the main variable in ignition time is the ratio of the fuel's total surface area to its volume. Since a twig's surface area is much larger than its volume, it ignites quickly. By comparison, a tree's surface area is much smaller than its volume, so it needs more time to heat up before it ignites.

As the fire progresses, it dries out the material just beyond it—heat and smoke approaching potential fuel causes the fuel's moisture to

A．Y

B．N

C．NG

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第3题

In a _____ of self-pity, he cried over his poor childhoo.

A.burst

B.thrust

C.rush

D.dash

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