維持綠卡的標準

https://www.uscis.gov/policy-manual/volume-12-part-d-chapter-2

USCIS reviews multiple factors when assessing whether an applicant objectively intended to abandon his or her LPR status,[34] including:

• Length of absence from the United States;

• Purpose of travel outside the United States;  (看工作性質，如果美國公司派到中國，好一些。)

• Intent to return to the United States as an LPR; (每年回來看孩子，has intent ) 

• Continued ties to the United States.(在美有房子有孩子, continued ties)