The main clause in the sentence is "Jimmy ran around the football field."
- "Jimmy" is the subject of the sentence, performing the action of the verb.
- "ran" is the main verb, indicating the action performed by Jimmy.
- "around" is a preposition that introduces a prepositional phrase "around the football field", which modifies the verb "ran" by indicating where Jimmy ran.
- "the football field" is the object of the preposition "around", and it functions as the location where the action took place.
Overall, the sentence is a simple declarative sentence in the past tense, and its function is to communicate the action of Jimmy running around the football field.