回复：一种假设, 大家研究一下. 希望能给一些人帮助.

来源: 于 2004-11-30 07:05:33 [旧帖] [给我悄悄话] 本文已被阅读：次

For F1, before you travel, ur school will endorse your I-20. SO they have record.

For H1, I am not sure.

However, if you go back to China, your Passport will have a stamp. This is hard evidence.