I-485 批準了，請好心人幫忙看看這是什末意思

我的I-485 在大約二十天前批準，但是沒有收到綠卡。最近收到下麵的email:

Current Status: Document mailed to applicant.

On July 2, 2007 we mailed the document to the address we have on file. You should receive the new document within 30 days. If you do not, or if you move before you get it, call customer service.

請問是不是綠卡已寄出還是需要補充材料？請好心人給個答複。 謝謝！