Questions & Answers about Puer mel amat, quia sapor eius dulcis est.
Puer is nominative singular. The nominative case is typically used for the subject of a sentence, and here the verb amat is third person singular, so puer fits as he loves.
Also, puer is a second-declension masculine noun, but unlike many second-declension nouns, it keeps the -er in the nominative singular instead of ending in -us.
Mel is the accusative singular here, the direct object of amat.
A learner might expect an accusative singular noun to end in -m, but that is not always true. Mel is a third-declension neuter noun, and for many neuter nouns, the nominative and accusative singular have the same form. So:
- nominative singular: mel
- accusative singular: mel