Combustion knock occurring in a diesel engine can be caused by _____.A.low coolant temperatureB.insufficient fuelC.high ambient temperatureD.carbon buildup on the injector tips
Combustion knock occurring in a diesel engine can be caused by _____.
A.low coolant temperature
B.insufficient fuel
C.high ambient temperature
D.carbon buildup on the injector tips
相关考题：
When you ______ at the door, I ______ some washing.A、knocked; didB、was knowcking; didC、knocked; was doingD、knock; am doing
Which statement describes the shore between Watch Hill Point and Point Judith?A.Low，rocky cliffs with heavily wooded hills inlandB.Sandy beaches broken by rocky pointsC.Sand dunes and beaches with a mud and sand bottomD.Wooded，barren hills with isolated prominent buildings
根据以下材料，回答There is little debate about the firstdevelopment of the energy system of the 22nd century--that most of the energyproduced on a large scale will be in the form of electric power. Thus, most presentconcepts for major long-term energy sources (solar, geothermal, fusion) are basedupon electric power production at central plants.The second major development is thepotential use of hydrogen as both a basic fuel to replace natural gas and aspart of a general system to convert, store and transmit electric energy overlong district by fuel cells, or it could be used directly as a fuel forcommercial, industrial or transportation purposes.Although hydrogen seems likely to play amajor role in the future as a form of energy transport and storage, other processesmay also be useful. Here we note only two possibilities.Flywheels: It appears to be workable toconstruct flywheels of almost any needed size that would be efficientconverters (93-95 percent) in first storing and then releasing electric power.In addition, the kinetic (动力的) energy ofrotation is easily converted to alternating electric power. But the engineeringis at an early stage of development, and a decade or more may pass before this potentialcan be reliably estimated.Batteries and fuel cells: some of the manybatteries being developed today look quite promising. Within a decade or two, abattery-operated electric auto might even become competitive with today′ s vehicles,at least for driving ranges up to 200 miles. An electric automobile would bepollution-free,and would probably be more energy-efficient than theinternal-combustion (内燃) engine.A fuel cell (which may be considered a hydridebattery) with about 40 percent conversion efficiency is expected to enter powerproduction on a large scale within about five years. Unlike steam-poweredgenerators, fuel cells can be made large or small and their efficiency inoperation is essentially independent of the loading. Thus they may avoid mostof the distribution costs of electric power as well as provide pollution-fleepower and offer opportunities for using the "waste heat" effectively.From the passage we can see that thefuel cell might be something ___________.A.with the electric energy stored in itwithout pollutionB.in which chemicals are containedC.in which certain fuels such as hydrogenare filledD.like a small steam generator
根据以下材料，回答There is little debate about the firstdevelopment of the energy system of the 22nd century--that most of the energyproduced on a large scale will be in the form of electric power. Thus, most presentconcepts for major long-term energy sources (solar, geothermal, fusion) are basedupon electric power production at central plants.The second major development is thepotential use of hydrogen as both a basic fuel to replace natural gas and aspart of a general system to convert, store and transmit electric energy overlong district by fuel cells, or it could be used directly as a fuel forcommercial, industrial or transportation purposes.Although hydrogen seems likely to play amajor role in the future as a form of energy transport and storage, other processesmay also be useful. Here we note only two possibilities.Flywheels: It appears to be workable toconstruct flywheels of almost any needed size that would be efficientconverters (93-95 percent) in first storing and then releasing electric power.In addition, the kinetic (动力的) energy ofrotation is easily converted to alternating electric power. But the engineeringis at an early stage of development, and a decade or more may pass before this potentialcan be reliably estimated.Batteries and fuel cells: some of the manybatteries being developed today look quite promising. Within a decade or two, abattery-operated electric auto might even become competitive with today′ s vehicles,at least for driving ranges up to 200 miles. An electric automobile would bepollution-free,and would probably be more energy-efficient than theinternal-combustion (内燃) engine.A fuel cell (which may be considered a hydridebattery) with about 40 percent conversion efficiency is expected to enter powerproduction on a large scale within about five years. Unlike steam-poweredgenerators, fuel cells can be made large or small and their efficiency inoperation is essentially independent of the loading. Thus they may avoid mostof the distribution costs of electric power as well as provide pollution-fleepower and offer opportunities for using the "waste heat" effectively.The energy we use most todayis___________A.solar energy B.geothermal energyC.hydrogen D.electricity
以下代码的执行结果是： n = 1 def func（a, b): n = b return a*b s = func（"knock~", 2) print（s, n)A．knock~ 1B．knock~knock~ 2C．knock~knock~ 1D．报错
以下代码的执行结果是： n = 1 def func（a, b): c = a * b return c s = func（"knock~", 2) print（c)A．knock~ 1B．knock~knock~ 2C．knock~knock~ 1D．报错