Pronouns that follow prepositions are different from other pronouns like subject pronouns (yo, tú, etc) and object pronouns (me, te, le, nos, os, lo, los, la, las).
Use the following pronouns after prepositions like
para → for
de → of/from
a → at/to
con → with
en → on,in
por → for, by
sin → without
Here are the pronouns that you use after prepositions:
*Note that these are almost the same as subject pronouns. The only difference is that yo changes to mí and tú changes to ti.
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Use the preposition a with one of these pronouns and a verb like gustar to add emphasis or to clarify to whom a verb is referring.
Me gusta comer → A mí me gusta comer.
A Juan le gusta comer. → Juan likes to eat.
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When you use the preposition con with the pronouns mí or ti, they combine to form a new word.
con + mí → conmigo (with me)
con + ti → contigo (with you)
by 