Prepositions are a part of speech. Prepositions usually are memorized in middle school. Prepositions link a noun to another noun. Prepositions really can only be learned by memorization. Some of the prepositions are in, under, over, with and through. You can find a list of prepositions at http://www.teachersparadise.com/c/prepositions-learning-charts-p-55386.html
