Let's identify the different elements in the sentence provided
- Subject: Leroy - which is the one who performs the action indicated by the verb
- Verb: to swim - the verb appears in present simple tense - the verb determines the action
- Direct object - there is not direct object in this sentence, because the verb is intransitive. Intransitive verbs are those which, because of their meaning, do not need to be complemented by an object.