Adverbs There are many similarities in form between adpositions and adverbs. Some adverbs are clearly derived from the fusion of a preposition and its complement, and some prepositions have adverb-like uses with no complement: {down the stairs}/downstairs, {under the ground}/underground. {inside (the house)}, {aboard (the plane)}, {underneath (the surface)} It is possible to treat all of these adverbs as intransitive prepositions, as opposed to transitive prepositions, which select a complement (just like transitive vs intransitive verbs). This analysis[16] could also be extended to other adverbs, even those that cannot be used as "ordinary" prepositions with a nominal complement: here, there, abroad, downtown, afterwards, … A more conservative approach is to say simply that adverbs and adpositional phrases share many common functions. [edit]Particles Phrasal verbs in English are composed of a verb and a "particle" that also looks like an intransitive preposition. The same can be said for the separable verb prefixes found in Dutch and German. give up, look out, sleep in, carry on, come to Dutch: opbellen ("to call (by phone)"), aanbieden ("to offer"), voorstellen ("to propose") German: einkaufen ("to purchase"), aussehen ("to resemble"), anbieten ("to offer") Although these elements have the same lexical form as prepositions, in many cases they do not have relational semantics, and there is no "missing" complement whose identity can be recovered from the context. [edit]Conjunctions The set of adpositions overlaps with the set of subordinating conjunctions (or complementizers): (preposition) before/after/since the end of the summer (conjunction) before/after/since the summer ended (preposition) It looks like another rainy day (conjunction) It looks like it's going to rain again today All of these words can be treated as prepositions if we extend the definition to allow clausal complements. This treatment could be extended further to conjunctions that are never used as ordinary prepositions: unless they surrender, although time is almost up, while you were on the phone [edit]Coverbs In some languages, the role of adpositions is served by coverbs, words that are lexically verbs, but are generally used to convey the meaning of adpositions. For instance, whether prepositions exist in Chinese is sometimes considered an open question. Coverbs are often referred to as prepositions because they appear before the noun phrase they modify. However, unlike prepositions, coverbs can sometimes stand alone as main verbs. For instance, in Standard Chinese, dao can be used in a prepositional or a verb sense