[图] When pressure is applied to a system in which...

When normal operating pressure is applied to the hydraulic oil used in a high-pressure system, the oil _____.

A.viscosity will decrease

B.volume will increase

C.volume will decrease

D.pour point will be reduced

The single acting cylinder is the simplest form. where pressure is applied to the full area of the piston head to move the load through piston rod extensionThe load causes rod _____ when the drive pressure is released.

A.contraction

B.retraction

C.expansion

D.shrinkage

Whether or not animals feel is not altogether an easy question to answer. A human being has direct awareness only of the pains which he himself suffers. Our knowledge of the pains even of other beings is only an inference from their words, and to a lesser extent their behaviour. Animals cannot tell us what they feel. We can, of course, study their bodily reactions to the kind of stimuli which would be painful to human beings and this has often been done. When such stimuli are applied to animals their pupils dilate, their pulse rate and blood pressure rise, they may withdraw the stimulated limb and they may make struggling movements. Nevertheless it has been pointed out that none of these reactions can safely be taken as indication that the animal experiences pain because they can all be evoked when the parts of the body stimulated have been isolated from the higher nervous centres. Furthermore, when disease produces such an isolation in human beings the corresponding stimuli are painless. We must therefore look for other evidence as to the capacity of animals to experience pain.

Basically, all the nervous elements which underlie the experience of pain by human beings are to be found in all mammalian vertebrates at least; this is hardly surprising as pain is a response to a potentially harmful stimulus and is therefore of great biological importance for survival. Is there any reason, then, for supposing that animals, though equipped with all the necessary neurological structures, do not experience pain? Such a view would seem to presuppose a profound qualitative difference in the mental life of animals and men, the difference between the human and subhuman nervous system lies chiefly in the much greater development of the human fore-brain. This would be significant in the present context only if there were reason to believe that it alone was correlated with the occurrence of conscious experiences. But much of our knowledge of the nervous regulation of consciousness is derived from experiments on animals.

Nevertheless, we cannot tell what pain means to an animal. We know from our own experience that pains differ greatly in their quality, severity and emotional accompaniments. We know, too, that experiences which in man would be fraught with intense and prolonged emotion cause only brief and fleeting disturbances in animals. The great development of the human forebrain is the basis of man's capacity for foresight, apprehension, and memory which so profoundly affects his experiences. It would be rash, therefore, to conclude that the pain which animals feel can be in all respects equated with that which human beings experience.

Which of the following is the best title for the text?

A．Animals and Pain

B．Human Beings and Pain

C．Painful Stimuli and Reactions

D．Nerve System and Pain

A.bunker at a normal rate

B.check for kinks in hose

C.close valves slowly

D.shut valves before topping off

With reference to a rotary vane steering gear system, which one of the following statements is true?

A.The three moving vanes and the three fixed vanes form. three pressure chambers

B.The three moving vanes and the three fixed vanes form. six pressure chambers

C.The three moving vanes and the three fixed vanes form. nine pressure chambers

D.The three moving vanes and the three fixed vanes form. twelve pressure chambers

The_______is a crystal which, under pressure, produces an electric current which varies with the pressure

A.alternator

B.glass thermometer

C.bourdon tube

D.piezoelectric pressure transducer

Which general weather conditions should you expect to find in a low pressure system ________．

A.Fair weather

B.Precipitation and cloudiness

C.Scattered clouds at high elevations

D.Gradual clearing and cooler temperatures

Why will a turbocharger diesel engine produce black smoke if excessive additional load is applied too quickly?

A.Exhaust energy would draw excess air

B.The inertia of the turbocharger rotor causes a time lag which delays the turbocharger speed increase

C.Exhaust gas pumping losses are increased due to turbine windage

D.Exhaust gas back pressure falls slightly due to increased nozzle action

听力原文： Heart failure is a condition in which the heart cannot pump as much blood as the body needs. This condition can begin with a heart attack or high blood pressure. The heart becomes weakened. Over time, it loses the ability to pump blood. A sign of heart failure is breathing difficulty. But people often mistake that for just a sign of aging.

In the United States, doctors say about five million people have this major cause of sickness and death. They say heart failure is the leading cause of hospital treatment for people aged sixty-five and older. But these doctors say the problem of heart failure has yet to be fully investigated.

Researchers at the Mayo Clinic in Minnesota did a study of the last twenty years. They expected to find that heart failure has become more common. Hospital admissions for heart failure have increased. But they found that the percentage of the population developing heart failure has not changed. Instead, survival rates have improved.

Which one of the following is a sign of heart failure?

A．Breathing difficulties.

B．High blood pressure.

C．Headache.

D．High body temprature.

According to the passage, the pressure to appoint women to corporate boards differs from the pressure to employ women in the work force in which of the following ways?

A．Corporate boards are under less pressure because they have such a small number of openings.

B．Corporate boards have received less pressure from stockholders, consumers, and workers within companies to include women on their boards.

C．Corporate boards have received less pressure from the media and the public to include women on their boards.

D．Corporations have only recently been pressured to include women on their boards.

E．Corporations are not subject to statutory penalty for failing to include women on their boards.