The materials are not prepared adequately, and sufficient materials need to be prepared before application. I can't apply for the extension of the principal of the student-origin student loan, because the materials in the application process are not fully prepared, such as proof of family financial situation, proof of my employment, repayment plan, etc. If some key materials are missing, it will make it impossible to apply for an extension. After preparing sufficient materials, I need to apply to the local social security department.