Questions about Object Pronoun Order
Q: Why is it yo lo mandé and NOT yo mandé lo?
Pronouns must come before the conjugated verb in Spanish, unless it there is an infinitive or a progressive verb to which the pronouns can be attached at the end, or a negative imperative verb that must have the pronouns attached at the end.
Q: Why is it Ella nos los trajo and NOT Ella los nos trajo?
Pronouns appear in a specific order. The indirect object pronoun me/te/le(s)/nos/os (usually referring to a person) must come before the direct object pronoun me/te/lo(s)/la(s)/nos/os. Remember to ask yourself the questions What is acted upon by the verb? (direct object) and Who is affected or benefits from the verb? (indirect object) in order to determine which is the indirect and which is the direct object.
Q: Why is it se los están devolviendo and NOT les los están devolviendo?
Remember that you cannot have two object pronouns in a row that begin with 'l', you must change the first pronoun to se.
Q: Why is the affirmative command dámelo and not me lo da?
For affirmative commands the object pronouns must be attached to the end of the verb.
Q: Why is it No se los mandes and NOT No mándesselos?
In negative commands, pronouns must come before the verb.