"He cuts the bag."
Vertaling:Hij snijdt de tas.
Hmm....you might get a bit of a laugh from a native speaker if you said that, as Zak on its own can have a vulgar meaning, whereas Tas does not. Besides, a bag can be a tas or a zak, but Zak is more often used with other descriptions, i.e. broekzak, rugzak, een zak appels, etc.