What do the total available limit, book balance, and available cash withdrawal limit of Bank of China credit cards refer to?

The total available credit limit is your total credit limit minus your current overdraft consumption.

The balance on the Bank of China credit card account is the current amount owed.

The credit card cash withdrawal limit is the amount of cash that can be withdrawn approved by each credit card.

The balance of the Bank of China credit card is a negative number, which is the deposit you currently have in the credit card, not the balance you owe.