黑下多年,可以和美國公民結婚拿綠卡嗎? Sure as long as

u are not in a deportation/removal proceedings. For a marriage GC, if u were in a deportation/removal proceeding at the time u were married, u either have to reside 2 years outside of US or have to prove by clear and convincing evidence to prove ur marriage is genuine.
Unless u do have enough documents to satisfy the DAo adjudicating ur case, hard.

If u never in a removal proc. u will be fine if u could prove the marriage is real by similar evidence mentioned above.

U may need a counsel who could guide u from the very beginning. If before the interview, sometime it's too late to get the required documents.