"The boys see the powerful horse."

Translation: Taobi kostōbe annī urnesi.

[NP_Dude]

Powerful horse is singular, but the answer is in plural. What am I missing?

[BorisPaing]

Hi. I've just checked on dothraki.org and anne belongs to the lunar type of the the fourth declension. That's why its accusative form is written annī, even when singular ;-)