Lists of all English prepositions are available on the EnglishClub website and the Grammar Revolution website, comprehensive as of 2015. The current EnglishClub list has 94 one-word prepositions and 56 complex prepositions. EnglishClub warns that it is impossible to produce a definitive list of English prepositions, because it is always possible to add new complex prepositions to the language.
The English language constantly changes and evolves as certain prepositions fall out of use and the meanings of other prepositions change. Together with postpositions and circumpositions, prepositions belong to a class of word known as adpositions. Adpositions express temporal or spatial relations, or various semantic roles.
A preposition comes before its complement, which is typically a noun, pronoun, gerund or noun phrase. Together, a complement and preposition form a prepositional phrase that often plays an adverbial role in a sentence. Some examples of prepositions are the one-word prepositions "before," "on" and "into," and the complex prepositions "according to," "in spite of" and "but for."
Exact translations of English prepositions into other languages are not always possible. Depending on the context, one English preposition may have several translations in the target language. Some common prepositions in English are "since," "at," "by," "through" and "about." Some pronouns have different uses in American English and British English.