回複：皮匠老師，能不能抽空解答下我換身份的問題，多謝

我是J2來美，後換成H1b, 現在正準備換成F1.
H1b將在年底12/31/2009結束，剛收到學校的I-20，開始時間是1/5/2010.請問
1.中間有5天的gap，要不要緊啊？
-No problem. You have 10-day grace period after your H1 expires and you also can enter/legally stay for one month in advance before the date your F1 start. So, both make you lawful presence after your H1 expires and before your F1 start.
會不會因為這5天而必須回國簽證？
-No.
2.如果F1在12/31/2009之前就批了，是不是立刻就不能工作了？
-You still can work until your h1 expires on 12/31/2009.
3.遞交I-539要求換成F1時，是不是要把I-20和I-94的原件寄過去啊？
-Correct, but keep the photocopies of these documents on your personal file.

多謝解答，實在不知道問誰這些問題。其他大俠若能解答也多謝了！