Adjustment of Status - I-485

We arrived very early, 1 hour ealier than our scheduled time. Checked-in at the counter and the lady told us we might have to wait for a long while.
So we were waiting in the lobby and chatting with other couples (It seems like the room is specially for couples),.

After two-hour waiting, we were called by an officer and we went to the interview office.
He began with some simple questions:
Where/when/how did you meet each other?
When is your spouse's DOB?
Why do you like your spouse?
What do you not like about your spouse?
Where do you live now?
Do you own the place or you rent?
Are you working now?
What do you do?

Then, he asked us to show him our original documents (Marriage certificate, Passport, Birth Certificate, and Naturalization Certificate, etc.)
And any additional documents, Joint bank account statement, photos, other joint documents.

The interview was pretty fast, took about 20 minutes.
At the end of interview, he printed out a receipt, saying "Your case is on hold for a background check" and told us if everything goes well, it might still take to up to 2 months to receive the green card.
However, 30 minutes later, I checked my case status online and it shows "New Card is being produced". I'm not sure if it means the background check has been done. But it looks fine.

Hope it can help the people who are still waiting.

Good luck, everyone!