{"p":"can-20","op":"mint","tick":"can","amt":"1000","rows":[{"df":"qa","content":[{"q":"In a blockchain, how can you determine if a transaction's recentBlockhash field has expired?","a":"In a blockchain, the method to determine whether the recentBlockhash  field of a transaction has expired is by comparing the timestamp of the field with the current timestamp. Firstly, obtain the timestamp of the recentBlockhash field of the transaction and the current timestamp, then calculate the difference between the two. If the difference exceeds the predefined expiration time, it can be judged that the recentBlockhash field of the transaction has expired. Additionally, based on actual business requirements, a reasonable expiration time can be set, such as adjusting the expiration time according to factors such as network delay and block generation speed."}]}],"pr":"4ce2405cc14913c4a463e2cd7749db70652c80c60ca5a88dab5638d228ffd266"}