legal ground
Article 27 of the Bidding Law
The bidder shall prepare the bidding documents in accordance with the requirements of the bidding documents. The bidding documents shall respond to the substantive requirements and conditions put forward in the bidding documents. If the project subject to tender belongs to construction, the contents of the tender documents shall include resumes, achievements and mechanical equipment to be used to complete the project subject to tender.
Article 46
The tenderer and the winning bidder shall, within 30 days from the date of issuance of the bid-winning notice, conclude a written contract in accordance with the tender documents and the bid documents of the winning bidder. The tenderer and the winning bidder shall not conclude other agreements that deviate from the substantive contents of the contract. If the tender documents require the winning bidder to submit the performance bond, the winning bidder shall submit it.