另外,我这次只给母亲申请,没有申请父亲。可是I-797C要求带“supporting evidence of your relationship, such as copies of any documentation regarding joint assets or liabilities you and your spouse may have together. This may include: tax returns, bank statements, insurance documents, property documents, rental agreements, utility bills, credit cards, contracts, leases, photos, correspondence and/or others."请问这是什么意思?是不是要带父母在中国的房产证?