A: The balance of payments consists of current account, capital and financial account, error and omission. Current account refers to goods, services, income and current transfer; Capital and financial items refer to capital transfer, non-production and non-financial assets transactions and all other financial accounts that cause changes in an economy's external assets and liabilities; Errors and omissions are artificially set items to balance the debit and credit of the balance of payments. First of all, according to the double-entry bookkeeping principle, both borrowers and borrowers must be equal in the end. Therefore, any deficit or surplus in current account and capital and financial account will inevitably be accompanied by the surplus or deficit of another project; Secondly, there is a financing relationship between current account and capital and financial account. The flow of real resources in the current account and the flow of asset ownership in the capital and financial accounts are two sides of the same problem. However, with the development of international financial integration, this financing relationship is gradually weakening. Capital and current account are not passively subordinate to current account, but have their own independent movement laws. Errors and omissions are based on the imbalance between current account and capital in financial accounts. If the sum of the first two items is the debit difference, the same amount will be credited, and vice versa.