Rules for writers, Tenth edition - Diana Hacker, Nancy Sommers 2021

Prepositions
Parts of speech
Grammar Basics

A preposition is a word placed before a noun or pronoun to form a phrase that modifies another word in the sentence. The prepositional phrase nearly always functions as an adjective or as an adverb.

To the summit functions as an adjective modifying the noun road; past craters functions as an adverb modifying the verb travels; from an extinct volcano functions as an adjective modifying the noun craters. (For more on prepositional phrases, see 49a.)

English has a limited number of prepositions. The most common ones are included in the following list.

Some prepositions are more than one word long: along with, as well as, in addition to, next to, rather than.

TIP: Prepositions are used in idioms such as capable of and dig up (see 18c). For specific issues for multilingual writers, see 31.