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我該填哪個表？
-I-864 and I-864EZ have the same function. Read the I-864EZ Instructions to see whether you are qualified for I-864EZ. If no, use I-864 which applies to any circumstance. If you don't have enough income to sponsor your mother, you need to ask your spouse to file I-864A to allow you to use his/her income for the support.

個人多少收入夠擔保母親一人的綠卡？
-Read this document:
http://www.uscis.gov/sites/default/files/files/form/i-864p.pdf