The credit card sub-card can pay. The secondary card, that is, the accessory card, is simply that this card is attached to the main card. Since it is affiliated, it means that this card is restricted by the main card and the main card has the right to control this card. This card is very useful. The main card and the auxiliary card use the same credit line, which is called credit line sharing in banking terminology. However, the credit limits of the two cards cannot be superimposed. However, the main card can limit the amount of the secondary card.