Questions & Answers about Serva mappam in scamno ponit, ne canis eam capiat.
In this sentence, serva is a noun, meaning female slave, maidservant, or servant girl, and it is in the nominative singular, which is the case normally used for the subject.
So:
- serva = the servant girl / the maid
- mappam = the direct object
- ponit = puts or places
A beginner might confuse serva with the imperative of servare (save! or keep!), but here the rest of the sentence makes it clear that serva is a noun: the servant puts the napkin...
Mappam is in the accusative singular because it is the direct object of ponit.
The verb ponere means to put or to place, and the thing being put is the direct object. So:
- serva = subject
- mappam = what the servant is putting
- ponit = puts
This is very common in Latin: the noun directly affected by the verb goes into the accusative.