And in 1784, John Hunter argued in much more detail, in a paper presented to the Royal Society of Edinburgh in its first year, that neither conjunctions nor adverbs were in all cases usefully distinguished from prepositions in English (or in Latin and Greek). He stressed that classifications were being based on the "merely accidental" differences in what constituent (if any) happened to follow the word. The rational analysis is to treat after as simply a preposition governing (optionally) a complement that can be either a noun phrase or a clause.In 1924, Otto Jespersen developed these ideas, pointing out that prepositions were the only lexical category defined by the type of complement. In other words, prepositions were defined as words that take a noun phrase (NP) complement. Verbs, though, take various complements, including object, goal complement, predicative complement, and no complement at all, in the case of an intransitive verb. Similarly, an adjective phrase may consist of an adjective alone or with a complement (e.g., I'm happy; I'm happy to be here). Jespersen also noted that many words, such as before in I came before, which were categorized as adverbs, were very similar in meaning and syntax to prepositions (e.g., I came before you.). And the same held for many words categorized as subordinating conjunctions (e.g., I came before you did.). He therefore proposed that all these words are prepositions, and that the requirement that they be followed by a noun phrase be dropped. This is the position taken in many modern grammars, such as The Cambridge Grammar of the English Language. On the other hand, dictionaries and ESL grammars have not adopted these ideas. For example, Merriam-Webster's Dictionary has before as an adverb, preposition, and conjunction. Preposition vs other lexical categories Prepositions vs verbs Both prepositions and verbs license NP objects, but in most cases, the distinction is clear because verbs conjugate, and prepositions do not. There are, however, a number of prepositions derived from participial verb forms (e.g., come or barring), which could be confused with verbs. Modification by really is typically possible with a VP (e.g., spring has really come) but not with a PP (e.g., the *flowers will bloom really come spring). Intransitive prepositions vs adverbs One of the results of the reconceptualization of prepositions by Jespersen and others (see ) is confusion between intransitive prepositions and adverbs. Many adverbs end in -ly, which clearly distinguishes