A preposition is a word used before a noun or pronoun to show its relation with some other word of the sentence. A preposition is generally used to show direction, location, time or spatial relationship or introduce an object. eg:- in, on, upon, with, by, till, to since, from, for, at, between, among, etc are prepositions.
- She is in the Kitchen. [here, in is a preposition used before Noun (Kitchen)]
In formal writing, it is general practice that a sentence should not end up in preposition, but in informal writing, a sentence can end up in preposition. Hence, we can say sometimes a preposition is not used before a Noun or Pronoun.
- I like the officers I am working with. (informal) [non-usage of preposition before the noun or pronoun]
- I like the officers with whom I am working. (formal)
- We have a lot to think about.
Prepositions of Direction
To refer to a direction, the prepositions to, in, into, on, onto, towards, for, along, across, up, down etc. are used.
Prepositions of Time
To refer to one point in time, the prepositions in, at, on, etc. are used.
Prepositions of Place
To refer to a place, the prepositions in (the point itself), at (the general vicinity), on (the surface) and inside (something contained) etc. are used.
Prepositions of Location
To refer to a location, the prepositions in (an area or volume), at (a point), and on (a surface). etc. are used.
Prepositions of Spatial Relationships
To refer to a spatial relationship, the prepositions above, across, against, ahead of, along, among, around, behind, below, beneath, beside, between, from, in front of, inside, near, off, out of, though, toward, under and within etc. are used.
A preposition can fall in more than one of the above categories like preposition in can be used to refer to time, direction location etc., thus there is a lot of ambiguity in the usage of a preposition as usage of preposition depends on the context of sentence. However as far as competitive exams are concerned questions are generally framed from some particular confusing pair of prepositions or prepositions governed by some rules. Now, we will discuss some confusing pairs of prepositions which are important for competitive exams.