The passbook has an annual interest rate of 0.4, and more bank cards have savings cards and credit cards on a regular basis. Credit cards are debit cards, and there is no interest on saving money. A savings card can be used as a current account or a time credit card. There are two restrictions, consumption and cash withdrawal. You can spend in advance, that is to say, you can spend first, and then use your credit card to pay interest during the interest-free period. However, your repayment is late and your interest is high.