Questions & Answers about Ich zeige diesem Mann den Park.
The verb zeigen is a ditransitive verb—it takes two objects. The person to whom you show something is always in the dative case. Since Mann is masculine, the dative singular of dieser Mann is diesem Mann.
The thing being shown is the direct object, which goes into the accusative. Park is masculine, so its accusative singular article is den. Hence den Park.
Both nouns are masculine, but they take different cases:
- Mann is the indirect object → dative singular → der Mann becomes dem Mann (or diesem Mann with the demonstrative).
- Park is the direct object → accusative singular → der Park becomes den Park.
Declension summary:
• Nominative: der Mann / der Park
• Dative: dem Mann / dem Park
• Accusative: den Mann / den Park