這是I-131的說明裏的一段（不信自己去看）

What If You Claim Nonresident Alien Status
on Your Federal Income Tax Return?

If you are an alien who has established residence in the United
States after having been admitted as an immigrant or adjusted
status to that of an immigrant, and are considering the filing of
a nonresident alien tax return or the non-filing of a tax return
on the ground that you are a nonresident alien, you should
carefully review the consequences of such actions under the
Immigration and Nationality Act.
You may also be inadmissible to the United States if you seek
admission as a returning resident, and you may become
ineligible for adjustment of status as a permanent resident or
naturalization on the basis of your original entry.
If you file a nonresident alien tax return or fail to file a tax
return, you may be regarded as having abandoned residence
in the United States and as having lost your permanent
resident status under the Act. As a consequence, you may be
ineligible for a visa or other document for which permanent
resident aliens are eligible.