Legal analysis: the supplementary clauses of the contract are valid by hand, but the handwritten part must be filled in and signed in the presence of both parties when signing the contract. The handwritten part is on the contract text held by both parties, above the signature. The handwritten part is the modification and explanation of the printed part, but it is only valid if both parties sign beside the handwritten part.

Legal basis: Article 5 10 of the Civil Code of People's Republic of China (PRC). After the contract comes into effect, the parties have not agreed or clearly agreed on the quality, price or remuneration, place of performance, etc. They can supplement the agreement; If a supplementary agreement cannot be reached, it shall be determined in accordance with the relevant provisions of the contract or trading habits.