A preposition is a word placed before a noun or pronoun to form a phrase modifying another word in the sentence. Therefore a preposition is always part of a prepositional phrase. The prepositional phrase almost always functions as an adjective or as an adverb.

across, over and through
on/to the other side of (line): across and overAcross and over can both be used to mean ‘on or to the other side of a line, river, road, bridge...
READ MORE
prepositions (1): introduction
meanings and use It is difficult to learn to use prepositions correctly in a foreign language. Most English prepositions have several different...
READ MORE
abbreviated styles
Some styles of writing and speech have their own special grammar rules, often because of the need to save space or time.1 advertisements and...
READ MORE
above and over
1 ‘higher than’: above or over Above and over can both mean ‘higher than’. Above is more common with this meaning.The water came up...
READ MORE
prepositions (2): after particular words and expressions
It is not always easy to know which preposition to use after a particular noun, verb or adjective. Here are some of the most common combinations...
READ MORE