单项选择题
A.after two unplanned service calls.
B.according to manufacturers specifications.
C.when the device is becoming unreliable.
D.every sixty days.
单项选择题 Whichofthefollowingtypeoflampisusedforheatingafuser？（）
单项选择题 Whenarrivingatthecustomerslocation，twodifferentusersdescribetheproblem，andfromtheirdescriptionitseemstobetwoseparateproblems.Whichofthefollowingisanappropriatesteptotake？（）
单项选择题 Whenonsiterepairingaprinterthetechnicianscellphoneringsanditisapersonalcall，howshouldthetechnicianhandlethis？（）