2. Prepositions: show relationship of one noun or pronoun to some other word in the sentence; often reflect spatial or time relationships

3. There are over 150 words in English that can function as prepositions
There are over 150 words in English that can function as prepositions. Here are the 25 most common:
about as
into
like
through
after
over
between
out of in to
for
with on at
from by
against
during
without
before
under
around
among

4. PREPOSITIONS only occur in little structures called PREPOSITIONAL PHRASES.
Prepositional Phrase = Preposition + its Object, which must be a noun (and its modifiers, if any) or pronoun.

5. Prepositional Phrase
in the morning
after class
by Shakespeare
with great difficulty
to them