German phrase
Das war meine Präsentation.
Meaning
That was my presentation
When to use it
Your presentation is over. Say this at the end, then ask if anyone has questions.
Example dialogue
Das ist meine Präsentation über meine Sommerferien.
This is my presentation about my summer vacation.
Das war meine Präsentation. Habt ihr Fragen?
That was my presentation. Do you have any questions?