5 About F2B & F3 kinds of family-based immigration(for U.S. citizen or permanent resident's adult children, over 18 years of age.):
Since the near future: (strongly recommended!)
Recommend to cancel F2B & F3 kinds of family-based immigration soon. (for U.S. citizen or permanent resident's adult children, over 18 years of age.)
Now:
If American citizens or permanent resident has handled family-based immigration for their adult children (over 18 years old), their adult children must be unmarried, when the waiting period will reach, their adult children can go to USA, and can be got the temporary resident status, they must go to work, or study abroad! They can't be got the permanent resident status of USA in a short term.