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Sweating of the refrigeration system compressor crankcase is caused by （）.
A . too much superheat
B . insufficient superheat
C . suction pressure too low
D . excessive refrigerant returning to the compressor
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The sudden reduction of pressure occurring within the crankcase of a refrigeration compressor during starting causes the （）.
A . sudden evaporation of wax crystals in the lubricant
B . sudden evaporation of entrapped air in the lubricant
C . release of refrigerant from the oil/refrigerant mixture
D . release of dissolved lubricant from the refrigerant
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Foaming of the oil in a refrigeration compressor crankcase is caused by （）.
A . refrigerant boiling out of solution from the lube oil
B . liquid refrigerant flooding the compressor and system
C . lube oil viscosity being reduced by refrigerant dilution
D . compressor suction pressure suddenly increasing
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Sludge may form in the crankcase of an air conditioning compressor as a result of （）.
A . bubbling refrigerant
B . overheating and oxidation
C . lowered operating temperatures
D . reducing the cloud or flash point
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If a diesel engine has been stopped because of piston seizure due to severe overheating, the crankcase（）
A . inspection covers should not be opened until the engine has cooled
B . ventilation system should be continued in operation for one hour for cooling
C . scavenge pump should be immediately secured to prevent loss of lube oil
D . explosion covers should be opened slightly to provide extra ventilatio
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Excessive oil foaming in the crankcase of a refrigeration compressor can result in （）.
A . overheated compressor bearings
B . excess lube oil viscosity
C . carbon deposits on the compressor piston rings
D . wax crystals forming in the lubricant
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In a normally operating diesel engine, the main cause of lubricating oil contamination in the crankcase is a result of the （）.
A . metal particles loosened by wear
B . air when no air cleaners are used
C . condensation of water vapors
D . breakdown of the lubricating oil by dilutio
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Sludge may form in the lubricating oil crankcase of a reciprocating air conditioning compressor as a result of （）.
A . wax precipitation in the lube oil
B . contamination by dust, scale, or moisture
C . refrigerant bubbles in the lube oil
D . refrigerant reducing the lube oil viscosity
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In a refrigeration system, foaming of the crankcase oil may cause the （）.
A . expansion valve to overfeed
B . compressor to knock
C . water regulating valve to fail
D . crankcase drains to plug
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When fuel enters the crankcase of a diesel engine, it （）
A . dilutes the lube oil and reduces its viscosity
B . forms sulfuric acid in the lube oil
C . causes pitting and failure of the bearings
D . causes sludge deposits on valve stem
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If water is found in the crankcase of a diesel engine, the cause may be due to（）
A . a cracked cylinder head
B . a leaky cylinder head gasket
C . a cracked cylinder liner
D . any of the above
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Regarding a Diesel engine crankcase, the general arrangement and installation should preclude the possibility of （）
A . free entry of air to the crankcase
B . water entering the crankcase while engine wash-downs are being performed
C . excessive oil leakage during periods of increased blow-by
D . sub-cooling internal component
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How dose water enter the crankcase of a diesel engine?（）
A . Through the crankcase exhauster
B . As water vapor contained in blow-by
C . Demulsifying lube oil passing through the main bearings
D . Condensation from vapor formed in the expansion tank
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Thousands of people died of starvation during the（）in that African country.
A . objection
B . poverty
C . consumption
D . famine
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Excessive oil foaming in the crankcase of a refrigeration compressor at start up can cause（）.
A . compressor damage from improper lubrication
B . refrigerant absorption by the lubricant
C . increased viscosity in the lubricant
D . carbon deposit on the compressor suction valve
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Which of the following conditions is most likely to occur when unburned fuel contaminates the crankcase of a diesel engine?（）
A . Lube oil is diluted and its viscosity is reduced
B . Sulfuric acid is formed
C . Bearings become pitted ad immediately fail
D . Valve stems develop sludge deposit
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In the story of the Happy Prince,the little Swallow died at the feet of the little prince .
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What is the protagonist Harry dying of?
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This is a very popular book in the U.S., but it died have a history of being banned in Europe, and it was still＿in many countries.
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Why does one of the monkey twins die?
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听力原文： Pope John Paul the Second has died at the age of 84 after leading the Roman Catholic Church for more than 26 years. The Polish-born pontiff died after suffering heart and kidney failure following two hospitalizations in as many months.
News of John Paul's passing was delivered to tens-of-thousands of people who gathered in Saint Peter's Square to light candles and pray for the pope. As they heard the news, some in the crowd raised their hands to their faces in disbelief, while others began sobbing uncontrollably. For many, John Paul was the only pope they ever knew.
John Paul's death marks the end of a reign that revolutionized the papacy. He traveled to more than 120 countries t6 minister to his widespread {lock of more than one-billion people. He built bridges to other faiths and confessions, and he spoke out forcefully in favor of the world's poor and oppressed.
How long had Pope John Paul been leading the Roman Catholic Church？
A．For more than 84 years.
B．For more than 26 years.
C．For more than 60 years.
D．For more than 30 years.
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The thought of dying slowly and painfully ______ me. I really can’t understand why so many people are opposed to euthanasia.
A．A. terrifies
B．B. curses
C．C. puzzles
D．D. injures
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Salt is as necessary to life as water. In many areas of Africa people once drank the urine (尿) of animals because they had no other source of salt. Without salt, human beings die.
The human body demands that the amount of salt in the blood always stay the same.When the body does not get enough salt, it protects itself by letting less salt leave the body in urine and sweat. But it cannot reduce this output to zero. Some salt is always escaping. On a completely saltless diet, like that of some people in Africa, the body steadily loses small amounts of salt through the kidneys (肾) and sweat glands (腺). It then tries to ad-just to this loss by speeding up its secretion (分泌) of water. In this way, the body attempts to keep the amount of salt in the blood at the necessary level. The result is a slow drying up of body and, finally, death. The person dies of thirst.
In cases where there is little or no water to drink, the body tries to do the opposite thing. Again, it must keep the salt level in the blood constant. Because it has little water, it attempts to stop water from leaving the body and to increase its secretion of salt. But, as with the escaping salt, it cannot be completely successful. Some water still leaves and the person eventually dies of thirst. In short, the body's normal needs for salt and for water are both parts of the same important need to keep the salt level in the blood constant.
Some African people once drank animal urine______.
A．when they were going to die
B．because they were thirsty
C．because there was little salt
D．because they were short of water
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Many animals in the forest died in last_____.
A.winter’s heavy snow
B.winter’s heavily snows
C.winter heavy snow
D.winter heavy snows
