● you will hEAr A ConvErsAtion ABout quAlity Control.● For EACh quEstion 23--30, mArk onE lEttErA,
B、orC、For thE CorrECt AnswEr.●AFtEr you hAvE listEnED onCE, rEplAy thE rECorDing. whAt is thE First stAgE oF quAlity Control
A、

A、visiting our suppliErs

B、

B、During proDuCtion

C、

C、ChEmiCAl AnAlysis