_____ allows for expansion and water make up in the water cooling system.

A．A top tank

B．A head tank

C．A head valve

D．A drain tank

[单选题]（） allows for expansion and water make up in the water cooling system.A . A top tankB . A head tankC . A head valveD . A drain tank

[单选题]A company is planning a $50 million expansion. The expansion is to be finan

[单选题]Aseasonticket_______theholdertomakeasmanyjourneysashewisheswithinthestatedperiodoftime.A)entitlesB)grantsC)bloomedD)promises

[单选题]A．(n)______ allows users to scramble and unscramble their messages easily without a third partyintruding．A．DESB．signing messagesC．encryptD．firebreak

[单选题](72) is a device that allows a computer to transmit information over a telephone line.(72) A．DiskB．ModemC．PrinterD．Display

[单选题]Maintenance activities include(74)。①making enhancements to software products②developing a new software product③correcting problems④adapting products to new environmentsA．①②B．①③④C．②③④D．①②③④

[单选题]A．llowances may be made for the expansion and contraction in piping by the use of expansion joints or ().A．UnionsB．Retractable flangesC．Union bulkhead fittingsD．Bends or loops in the line

[单选题]A． thermostatic expansion valve is properly controlling evaporator superheat. Adjusting this valve to lower the superheat will result in a/anA．evaporator pressure decreaseB．evaporator coil over-feedC．evaporator capacity increaseD．expansion valve diap

[单选题]The expansion valve used in a refrigeration system regulates theA．superheat of the gas leaving the compressorB．back pressure in the evaporatorC．temperature in the refrigerated spaceD．degree of superheat of the gas leaving the evaporator

[单选题]When replacing a thermostatic expansion valve sensing bulb, it is necessary toA．apply a light film of oil to increase heat transferB．apply a light film of oil to prevent oxidationC．apply a heavy coating of grease to function as a heat sinkD．carefully