Your are right.

是不是说， 如果在美国待满一年， 申请到N-470， 就可以回国长期工作。 五年就可以拿绿卡了。那样， 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.