8老师，485这么说的，有点不清楚

Family-based preference categories include: unmarried sons and daughters (21 years of age and older) of U.S. citizens; spouses, unmarried children (under 21 years of age) and unmarried sons and daughters (21 years of age and older) of lawful permanent residents; married sons and daughters of U.S. citizens; and brothers and sisters of U.S. citizens (if the U.S. citizen is 21 years of age or older).
If a visa is immediately available, applicants filing under a family-based preference immigrant category do not have to wait until Form I-130 is approved to file Form I-485. If a visa is immediately available, you may file your Form I-485 together with your Form I-130, while Form I-130 is pending, or after your Form I-130 is approved. Otherwise, you may file your Form I-485 only after your Form I-130 is approved and a visa is immediately available. See the When Should I File Form I-485 section for more information.

前面说可以不用等到130批，后面又说otherwise , 必须130批并且签证有名额，我的是F2B. 这里到底是什么意思？

所有跟帖： 

• Reply -863211- ♂ (1760 bytes) () 06/07/2019 postreply 20:47:01

• 8老师: 我知道签证有名额，但是485 instruction page 20, 最后这样写“Otherwise, you m -shaoz- ♀ (74 bytes) () 06/07/2019 postreply 21:04:17

• 8老师: 我知道有名额，485 instruction 20页说Otherwise, you may file your For -shaoz- ♀ (60 bytes) () 06/07/2019 postreply 21:07:11

• 8老师：485 说明你20页这么说的 -shaoz- ♀ (684 bytes) () 06/07/2019 postreply 21:09:52

• Up to you. -863211- ♂ (0 bytes) () 06/07/2019 postreply 21:40:11