Final answer:
The bolded word 'under' is a preposition that shows the relationship between 'shoes' and 'kitchen table'.
Step-by-step explanation:
The bolded word in the sentence 'I left my shoes under the kitchen table' is a preposition. Prepositions are words that show the relationship between a noun or pronoun and another word in the sentence. In this case, the preposition 'under' shows the relationship between 'shoes' and 'kitchen table'.
Learn more about Parts of speech