你給的第一個link裏麵隻是說如果Declare yourself a “nonimmigrant” on your tax returns就會失去綠卡。但是我雖然是綠卡，並且想用treaty報稅，我並不會說自己是nonimmigrant啊。而且我印象中1040表裏麵也沒有什麽地方填自己的immigrant status啊。
-If you file 1040NR, your GC may be cancelled. If you file 1040 (this form is for residents such as H1 hdoler, GC holder, US citizen, etc.), you will be fine.
另外，第二個問題如果回答是Yes，不就說明綠卡也能用treaty麽？這不正好說明pjiang的說法不對嗎？
-What I said is that if you were not green card holder in several months in one year, then became a GC holder in the same year, you can use the treaty benefit for the time (several months) when you were non-GC holder (if qualified), but you can not use the treaty benefit from the date you became the GC holder (the later months of 2010). Please note that you file the tax return is for 2010 when you were not GC for the 前半年 of 2010 even if you are GC holder now when you file 1040.
你給的第二個link是關於dual status的。我的情況不是這樣。我2010年全年都是resident alien。雖然前半年是J1，但是J1從第三個calendar year就算是稅務上的resident alien了，
後來年變成綠卡就更是resident alien了。但是根據前人的經驗和我自己的理解，resident alien照樣可以用treaty的。
-You need to check the US-China Treaty to see whether you were still qaulified for the benefit for the 2010 前半年J1. If yes, you can use it even if you file 1040 (not 1040NR).
