1)父母10年前visa 延期有过A#,申请绿卡应该用同一个A#吗?-No.
如果记不住是否可以leave it blank?-Yes. Leave it blank.
2) form I-130 D2 asks "if you have even filed petition for this or any other persion...", does the previous visa extension count?
-Not count. It means I-130 filing.
I read somewhere this is targeted to spouse, not sure how to answer this question.