1. In a contract with a specific object as the subject matter, when the object matter is lost, the actual performance of the object matter is no longer possible.
 2. If the obligor fails to deliver the subject matter on time, the actual performance is unnecessary to the obligee or will harm the obligee's own interests.
 3. If the quality of the subject matter does not meet the requirements of the contract, the obligee waives the request for actual performance.
 [Legal Basis]
 In Article 509 of the Civil Code, the parties shall fully perform their obligations as agreed.
 The parties shall abide by the principle of good faith and perform the obligations of notification, assistance, confidentiality, etc. according to the nature, purpose and trading habits of the contract. In performing the contract, the parties shall avoid wasting resources, polluting the environment and destroying the ecology.