我记得以前是说如果主申请人485 pending,副申请人也可以单独递485的。但我看485说明上说 "副申请人单独递485要不与主申请人的485一起递，要不就在主申请人的485批准之后",不知道是不是我理解错了?
2.Based on being the spouse or child (derivative) at the time
another adjustment applicant (principal) files to adjust
status or at the time a person is granted permanent resident
status in an immigrant category that allows derivative status
for spouses and children.
A. If the spouse or child is in the United States, the
individual derivatives may file their Form I-485 with Form I-485
for the principal applicant, or file Form I-485 at
anytime after the principal is approved, if a visa number is
available.
请问这个 "derivatives may file their Form I-485 with Form I-485
for the principal applicant" 必须是同时递吗？