"The woman drinks milk."
Translation:De vrouw drinkt melk.
Dutch has two genders. German has three. If a word is masculine or feminine in German, it is almost always a de word in Dutch. If it is neuter in German, then it is almost always a het word in Dutch. Der Mann=de man. Die Frau=de vrouw. Das Kind=het Kind. So far, the only exception I have found is "the menu." The menu is die Speisekarte in German but het menu in Dutch.
It would be wrong to put "de" between "drink" and "melk" because Duolingo is asking you to say "The woman drinks milk". "De" means "the", so throw in a "de" and the sentence becomes "The woman drinks THE milk".