单项选择题
A.Trash can
B.Burial
C.Recycling center
D.Storage shed
单项选择题 Whichofthefollowingcanconserveenergyinaserverroom？（）
单项选择题 AcorporationplanstoreplaceolderofficePCswithenergyefficientpersonalcomputersintheir24hourhelpdeskdepartment.WhichofthefollowingwouldbetheBESTchoice？（）
单项选择题 Whichofthefollowingtermsisusedwhenprintingdataonboththefrontandthebackofpaper？（）