Verbs are the part of speech that makes the most use of prepositions. A verb that uses the preposition ant is dėti (to put).

The present tense 3rd person of dėti is deda. The case that dėti requires is the accusative:

Jis deda knygą. He is putting the book.

We can also include a preposition among the objects of this verb:

Jis deda knygą ant stalo. He is putting the book on the table.

So for the word dėti (and all other verbs) you must memorize:

• its forms: dėti, deda;
• the case that it requires: accusative;
• the preposition that it often uses: ant.