Hello Luca~I am chinese,maybe i can give some ideas for you^^ In chinese,there are many prepositions,such as 为,向,给,朝,到,往,在……etc,and they are divided according to Time,purpose,reasons and so on,just like English does.The key is,you need to distinguish the language environment this sentence belongs to,and then choose the best word to describe.^^hope it's hopeful~