English says Marina's bike or the door of the house. Finnish adds -n to the owner, which comes first:

• Marinan pyörä — Marina's bike
• Marcosin koira — Marcos's dog (a name ending in a consonant adds -in)
• talon ovi — the door of the house
• Helsingin tori — Helsinki's market square

To ask whose?, say Kenen? — Kenen koira tämä on? — Whose dog is this?