我今年是要到美国念PhD的新生 学校发给我的I-20是给加拿大护照的 SEVIS线上也完成缴费 以下是我在网站上找到入境所需资料的资讯 https://ca.usembassy.gov/visas/canadian-students/ 1. A Canadian passport; 2. The original I-20 (or DS-2019) certificate; 3. Proof that the SEVIS fee has been paid; 4. Proof of ability to pay school fees and living expenses in the United States; 5. Proof of ties to Canada. 我的困惑是第五项Proof of ties to Canada到底是什么 我大部分的时间都待在台湾生活 是有一些亲戚在加拿大 请问有人有相关经验吗?