You are considered a resident alien if you met one of the following two tests for the calendar year:
The first test is the "green card test". If at any time during the calendar year you were a lawful permanent resident of the United States according to the immigration laws, and this status has not been rescinded or administratively or judicially determined to have been abandoned, you are considered to have met the green card test.
The second test is the "substantial presence test". For the purposes of this test, the term United States includes the following areas:
- All 50 states and the District of Columbia
- The territorial waters of the United States, and
- The seabed and subsoil of those submarine areas that are adjacent to U.S. territorial waters and over which the United States has exclusive rights under international law to explore and exploit natural resources
To meet the substantial presence test, you must have been physically present in the United States on at least 31 days during the current year, and 183 days during the 3 year period that includes the current year and the 2 years immediately before. To satisfy the 183 days requirement, count all of the days you were present in the current year, and one-third of the days you were present in the first year before the current year, and one-sixth of the days you were present in the second year before the current year.
根據IRS文件，當年一天算一天，前一年隻能3天算一天，前2年隻能6天算一天。
然後又加上下麵這個，如果父母在國內有退休金有房產，嚴格來說，即使滿足了183天，也不能報dependent了。
Even if you meet the substantial presence test, you can be treated as a nonresident alien if you are present in the United States for fewer than 183 days during the current calendar year, you maintain a tax home in a foreign country during the year, and you have a closer connection to that country than to the United States. This does not apply if you have applied for status as a lawful permanent resident of the United States, or you have an application pending for adjustment of status. Sometimes, a tax treaty between the United States and another country will provide special rules for determining residency for purposes of the treaty. An alien whose status changes during the year from resident to nonresident, or vice versa, generally has a dual status for that year, and is taxed on the income for the two periods under the provisions of the law that apply to each period.
