Prepositions indicate relationships between words or ideas. Most prepositions deal with location and are easy to learn.
in spite of
in front of
*These can also be used as conjunctions.
Some prepositions, however, have more than one meaning and can be very confusing.
Generally, in, on and at indicate location. See also: Prepositions of Location
To and from imply movement toward or away from something. However, to can also function as part of an infinitive. See also: Infinitives.
To and for can introduce indirect objects. See also: Indirect Objects
For and since can also indicate duration. See also: Present Perfect Progessive
Of is used in partitives (all of, some of . . .) and other expressions. See also: Quantifiers
Many prepositions are also used in expressions. See also: Grammar: Preposition Collocations with "Be"; Verb and Preposition Collocations