回複：從加拿大回美國到底要不要簽證？

Yes, no problem. you can use I-94 and any expired visa to come back to US at land port or air port, or sea port if you stay in canada less than 30 days. I did so many times with J-1 94 and expired J-1, H-1 94 and expired B-1 ( I did not have H-1 visa, Because I changed from B-1 to H-1).