The original sentence is "she has this apparent innocence which, I suspect, she uses to her advantage." (Cambridge Advanced Learners Dictionary, 4th).
I understand that "she has this apparent innocence" == Subject + transitive verb + Object;
"which" guide as an Attributive clause;
"I suspect" is a parenthesis;
However, I have a little confused with the sentence "she uses to her advantage",
Because "I" is a subject, "uses" is a transitive verb, why can a transitive verb accompany with a prepositional phrase, "to her advantage"?
I remember that the transitive verb only accompanies with one or more objects such as a Noun, a to-infinitive and some kinds of clauses but not a prepositional phrase.