隻要他或她滿足substantial presence test 仍然能當成 resident alien
substantial presence test
1. 31 days during 2011, and
2. 183 days during the 3-year period that includes 2011, 2010, and 2009, counting:
a. All the days you were present in 2011,and
b. 1/3 of the days you were present in 2010, and
c. 1/6 of the days you were present in 2009
