1. Approval process: The loan approval process of China Bank includes multiple links, including data review, credit evaluation and collateral evaluation. Each link will take some time to complete, so the whole approval process will take five days.

2. Staffing: Bank of China has limited loan approval personnel and needs to handle a large number of loan applications. The number of applications is large, and the approver needs to spend more time processing each application, so the approval time will be extended.