shaoyao, I feel I have some responsibility to further
study your issue since I told you to extend your F1.
The last thing I want to do is to mislead you. So
first, I suggest you ask a GOOD lawyer.
there is discussion at
http://boards.immigrationportal.com/showthread.php?t=115661
Someone in this discussion says:
"well, it's certainly an interesting issue. My school's International Center recommends that you maintain F-1 status (by not getting AOS EAD and by not working with it and not travelling on AP) even after you apply for AOS. Also, maintaining full-time enrollment and other attributes of maintaining F-1 status are a must. In this case, they told us, if your I-485 is rejected, you are still in F-1 status and can continue being in it without a need for reinstatement.
They had an information session with INS last year, whereupon this recommendation was offered to my school by INS."