Translation:Are you Terrans? No, we are not Terrans.
The structure of these exercises is quite clever. It lets you see two different verb forms at once and compare them and learn the pattern and stem. :D
I agree that it's a little strange at first, but it makes sense from the Klingon perspective. For anyone not from Earth, the planet is called Terra Firma. What would you call the dominant race from Terra Firma? Terrans.