Your are right.

是不是說， 如果在美國待滿一年， 申請到N-470， 就可以回國長期工作。 五年就可以拿綠卡了。那樣， 太爽。。。

From USCIS.

Please note that in most cases you must have been physically
present and residing in the United States for an uninterrupted
period, without any absences whatsoever,for at least one
year after your admission as a lawful permanent resident
before you can file a Form N-470.
In addition, you must submit the Form N-470 to USCIS
before you have been absent from the United States for a
continuous period of one year. However, if your absence
from the United States is, was or will be solely as a clergyman
or clergywoman, missionary, brother, nun or sister of a
religious denomination or interdenominational mission
organization having a bona fide organization within the
United States, you may file this application before or after an
absence of one year or more.