I am a exchange student from china. Now I come to canada for one semester exchange study with a Sx-1 visa. But now I want to exchange for another sememster in Spring next year. And I should travel back to china after this sememster to deal with some affairs and then reenter canada so only an extension for visa is not proper. Is it necessary for me to apply for a study permit? It might be too time consuming to do so. Whether it is possible that I apply for another sx-1 because the next sememster is also shorter than six months. And can I apply this while I am still in Canada or I can only apply after leaving Canada? The time interval is short so I really want to get another visitor visa within Canada.