回複：在加拿大機場被拒

Usually, if you are a student in Canada, you should have
a mutiple entry visa during your study period unless it has
expired. But to reenter Canada from US, you can use your study permit only(WITHOUT entry visa). I think the US officer in Canada airport suspect that you will stay in US
without leaving, and the main reasion is that you did not
give a good explaination why you go to US and saty for a month during the semester, and how you can manage study in
Canada. I think if you go to US in winter or summer break,
you will not have any difficulties even without entry visa(of course valid study permit is needed). But if you
go to state for a month during a semester, you still
have troubles even you get an entry visa to Canada.

I have too much experience, if you like, you can call me
at 1-514-486-7008.