The cases on the validity of contract mainly involve two aspects: one is the case of whether the contract is valid; the other is the case of invalid contract. In the former category of cases in the main question is to require candidates to determine whether the contract is valid, the test is the candidates of the contract of the understanding and application of the elements of the validity of the case; the latter category of cases of the main question is for the contract is invalid for specific reasons, such cases can be divided into several: the subject of the contract is not qualified for the case, the case of the contract is not lawful, due to duress, fraud and the conclusion of the contract, the form of the form does not have the legal requirements and lead to The case of invalid contract and the agent illegal contract on behalf of the invalid case. Among them, the conclusion of contracts beyond the scope of business, the conclusion of contracts by agents in violation of the law, and the conclusion of contracts without the ability to perform are often the key questions. The above two aspects may also be combined together. For example, company B transferred a piece of land use right owned by company A, company A paid the transfer fee. Soon, company B on the same piece of land and company C signed a land use right transfer contract, and assisted company C for the land use right transfer registration procedures. Now company A and company C on the land use right belonging to the dispute, both parties to the court.

Q: Who owns the right to use the land and why?

Method of analysis: according to the case, the use of the substantive and formal elements of a valid contract, to determine whether the contract is valid. Valid contract, should be performed, otherwise, constitutes a breach of contract, the defaulting party to bear the responsibility of breach of contract. If the contract is invalid, to find out what is the reason for invalidity? Belong to which kind of invalid contract? Invalid contract, shall not be performed, has begun to perform to stop performance, the party does not perform, not bear the liability for breach of contract. For the invalid contract, to distinguish the fault of the parties, the party at fault to compensate for the other party's losses, both parties are at fault, should be returned to both sides. If both parties intentionally conclude an illegal contract, the property acquired or agreed to be acquired by both parties shall be returned to the state treasury. In the above case, A and B contract is invalid (due to violation of state law on the transfer of land use rights should be registered), so A can not obtain the right to use the land, while the contract between B and C is a valid contract, C obtained the right to use the land according to law.