A.aftertwounplannedservicecalls.
B.accordingtomanufacturersspecifications.
C.whenthedeviceisbecomingunreliable.
D.everysixtydays.
参考答案:B
A.aftertwounplannedservicecalls.
B.accordingtomanufacturersspecifications.
C.whenthedeviceisbecomingunreliable.
D.everysixtydays.
参考答案:B