I have a question about when to use "to" and when to use "for". In the following sentence from my report my instructor change the preposition "to" to "for" and I don't know why he did that:
"Here, the cardio exercise to be effective in burning fat, the fat burning zone should be determined to that person."Although, I feel the sentence is correct with the preposition "to". But, I don't know why it was wrong with preposition "to".
I would be gratefull if somebody would explain me what is going on behind these 2 prepositions with some clear examples.