A Simple Guide To Prepositions

A Preposition is a word that comes before a Pronoun or a Noun and expresses the relationship between Noun or Pronoun and some part of the remaining sentence.
(a) He is busy with his work. (b) The boy jumped into the river. (c) The birds are chirping in the trees.
 
In these sentences the words with, into and in show the relationship between the verbs busy, jumped and chirping with the nouns work, river and trees respectively.

Position of the Preposition
A. A Preposition usually precedes its object. 
(i) He laughs at the poor. (ii) He is angry with you. (iii) She agrees with me. 

B. In the case of Relative Pronouns it comes after the subject.

(i) This is the boy whom I was looking for. (ii) That is the pen whose mention I was making of. 

C. In the following cases, the Preposition comes after its object.

(i) Where is the boy you were complaining against?

(ii) What things are there you are looking for?

(iii) Who is there, you are waiting for?

Omission of the Prepositon
In many cases when the sentences contain Nouns of Time or Place, the Prepositions from, in and for are often omitted.
(i) He walked many kilometres. (ii) He came to see me last year. (iii) As I could not find my puppy anywhere, I looked here and there.

Prepositions are small words that show the relationship between one word and another. Prepositions in the following sentences show the position of the paper in relation to the desk, the book, hand and the door.
The paper is on the desk.
The paper is under the book.
The paper is in his hand.
The paper is by the door.

Common Prepositions
about
at
by
in
onto
toward
above
before
concerning
inside
out
under
across
behind
despite
into
over
until
after
below
down
like
since
up
against
beneath
during
near
through
upon
along
beside
except
of
throughout
with
amid
between
for
off
till
within
among
beyond
from
on
to
without