Pdf format is the protection of your documents, usually taken from the computer before uploading. Take a look. If the website is not closed before the last time, you can delete it and upload it again. Please enter the project management system of the National Natural Science Foundation as soon as possible to see if your project has been returned. If it is returned, please ask the project applicant to complete the repair of the full text of the results in the resume as soon as possible and regenerate the PDF file. The specific reasons for the return can be viewed through "Return Reasons" on the application list page. Please log in to the system as soon as possible to see if your application status has been returned.