"The boy reads his books."
Translation:Drengen læser sine bøger.
You have two genders in Danish, there's no good rule and you have to learn by heart which noun goes with what gender.
Examples for common gender:
a man = en mand; the man = manden
a woman = en kvinde; the woman = kvinden
Examples for neuter:
an apple = et æble; the apple = æblet
a salt = et salt; the salt = saltet