我記得 IRS 網站上有詳細介紹的, 我剛google 了沒在 IRS 上找到, 但是找到以下信息, 估計也是 copy from IRS:
http://www.cgrcpaonline.com/MENU/news/residentaliens/residentaliens.asp
Resident Aliens ... You are a resident alien of the United States for tax purposes if you meet either the green card test or the substantial presence test for the calendar year (January 1–December 31). ...
Green Card Test ...
the option of Dual-Status Aliens may be applicable to your situation