Legal analysis: the fact of borrowing can be proved by collecting relevant witness testimony, transfer records, chat screenshots, IOUs and other evidence materials. The borrower shall repay the loan within the agreed time limit. If there is no agreement or unclear agreement on the loan term, the borrower may return it at any time; The lender may urge the borrower to return it within a reasonable period of time.

Legal basis: Article 26 of the Provisions of the Supreme People's Court on Several Issues Concerning the Application of Laws in the Trial of Private Lending Cases. The loan amount specified in debt certificates such as IOUs, receipts and IOUs is generally recognized as the principal. If interest is deducted from the principal in advance, the people's court shall confirm the actual amount lent as the principal.