Windows 2000是基于下列哪一个版本的Windows操作系统发展而来的？

A.Provide dynamic IPaddressesforDSIs.

B.Provide connectivity to DHCP servers on other subnetworks.

C.Provide dynamic IP addresses for SRC applications.

D.Provide dynamic IP addresses from pools used for PPPoE subscribers.

Which of the following statements concerning fire-tube boilers is correct？ .

A.Combustion gases flow through the tubes

B.Flames impinge on the tubes

C.Combustion occurs in the tubes

D.Water flows through the tubes

Which of the following statements concerning energy is correct？

A.Energy can be created or destroyed

B.Energy may not be transformed

C.The total quantity of energy in the universe is always the same

D.None of the above

Which of the following statements is correct concerning the viscosity of lubricating oil？

A.Viscosity will increase as temperature increases

B.Viscosity is a measure of a fluid s internal resistance to flow

C.Viscosity will decrease as temperature decreases

D.Viscosity is not dependent on temperature

Which of the following statements is correct concerning the “flash point” of a liquid？

A.It is lower than the ignition temperature

B.It is the temperature at which a substance will spontaneously ignite

C.It is the temperature at which a substance, when ignited, will continue to bum

D.It is the temperature at which the released vapors will fall within the explosive range

Which of the following statements concerning butterfly valves is correct？

A.Special tools are required for lapping or grinding

B.It is impossible to throttle flow with a butterfly valve

C.To close the valve, it is only necessary to turn the handle a quarter of a turn

D.The butterfly valve should never be used in a freshwater system

Which of the statements concerning children' s fare is true？

A．Children under two are charged 10% of the normal fare under any circumstances.

B．The second child under two accompanying the same adult is charged 50 % of the normal fare.

C．A 12-year-old is charged 50% of the normal fare.

D．Unaccompanied children are charged the normal fare.

Which of the statements concerning children's fare is true？

A．Children under two are charged 10% of the normal fare under any circumstances.

B．The second child under two accompanying the same adult is charged 50% of the normal fare.

C．A 12-year-old is charged 50% of the normal fare.

D．Unaccompanied children are charged the normal fare.

Which of the listed statements is correct concerning the starting of centrifugal pumps？ .

A.They should always be started with the discharge valve closed

B.They should always be started with the discharge valve opened

C.A priming pump is always required to flood the impeller suction

D.They should always be started with the sealing line valves closed

Which of the following statements concerning Tennessee Williams is NOT correct？

A．He has been influenced by Anton Chekhov,D. H. Lawrence and Hart Crane.

B．His last Broadway play is named Clothes for a Summer Hotel.

C．The recurrent themes in many of his plays are loneliness and desire.

D．He was awarded Nobel Prize for his brilliance as a dramatist.