Claiming the income was acquired from a non-taxable source such as a loan or a gift (especially if the gift-giver lives overseas or is dead so is not available for cross-examination).

• 主张财产是通过免税途径取得的，比如贷款和赠与(尤其是当赠与人居住在海外或已经死亡从而不能被交叉质证)。