发邮件问了下usps他们的答复如下Our tracking information is updated once an item is processed through a postal facility. Once an item is processed through a postal facility, the tracking will update with the location and time of processing. While an item is in transit from one facility to the next, the Postal Service cannot track a item, we can only assume that the item is in transit. The only service that allows for accountability at every step of way is Registered Mail. With Registered Mail service, each individual that encounters and processes the mail item must sign for it until the item reaches its final destination. Until your package receives a tracking update, we will not have any additional information regarding your item.