If you've paid all your property taxes, you are given a da chan zheng, or "big" property certificate. If you haven't yet paid, you can only get a "small" property certificate, and you can't sell your property. Some buildings can be bought with a loan, but others can't.
不同的房子又有不同的身分證明，如大產證、小產證，有的房子可申請「按揭」（貸款），有的又不行，種類繁雜。