Civil Code-Book III Contracts-Title One General Provisions-Chapter IV Performance of Contracts（a）
Chapter IV Performance of Contracts
第四章 合同的履行
Article 509 Each party shall fully perform its own obligations as agreed.
第五百零九条 当事人应当按照约定全面履行自己的义务。
The parties shall abide by the principle of good faith, and perform obligations of notification, assistance, and confidentiality, etc. in accordance with the nature and purpose of the contract and the transaction practice.
当事人应当遵循诚信原则，根据合同的性质、目的和交易习惯履行通知、协助、保密等义务。
When performing a contract, the parties shall avoid wasting resources, polluting the environment, and destroying the ecology.
当事人在履行合同过程中，应当避免浪费资源、污染环境和破坏生态。
Article 510 Where, after the contract becomes effective, there is no agreement in the contract between the parties on such contents as quality, price or remuneration, or place of performance etc., or such agreement is ambiguous, the parties may agree upon supplementary terms through consultation; if a supplementary agreement cannot be reached, such terms shall be determined in accordance with the relevant provisions of the contract or transaction practices.
第五百一十条 合同生效后，当事人就质量、价款或者报酬、履行地点等内容没有约定或者约定不明确的，可以协议补充；不能达成补充协议的，按照合同相关条款或者交易习惯确定。
Article 511 Where certain contents agreed upon by the parties in the contract are ambiguous and cannot be determined in accordance with the provisions in the preceding article, the following provisions shall be applied:
第五百一十一条 当事人就有关合同内容约定不明确，依据前条规定仍不能确定的，适用下列规定：
(1) If quality requirement is not clear, performance shall be rendered in accordance with the state mandatory standard; absent any state mandatory standard, performance shall be rendered in accordance with the state voluntary standard; absent any state voluntary standard, performance shall be rendered in accordance with the industry voluntary standard; or absent any state or industry standard, performance shall be rendered in accordance with the customary standard or any particular standard consistent with the purpose of the contract.
（一）质量要求不明确的，按照强制性国家标准履行；没有强制性国家标准的，按照推荐性国家标准履行；没有推荐性国家标准的，按照行业标准履行；没有国家标准、行业标准的，按照通常标准或者符合合同目的的特定标准履行。
(2) If price or remuneration is not clear, performance shall be in accordance with the prevailing market price at the place of performance at the time the contract was concluded, and if adoption of a price commissioned by the government or based on government issued pricing guidelines is required by law, such requirement applies.
（二）价款或者报酬不明确的，按照订立合同时履行地的市场价格履行；依法应当执行政府定价或者政府指导价的，依照规定履行。
(3) When the place of performance is not clear, if the obligation is payment of money, performance shall be at the place where the payee is located; if the obligation is delivery of an immovable, performance shall be at the place where the immovable is located; for any other subject matter, performance shall be effected at the place where the party performing the obligations is located.
（三）履行地点不明确，给付货币的，在接受货币一方所在地履行；交付不动产的，在不动产所在地履行；其他标的，在履行义务一方所在地履行。
(4) If the time limit for performance is not clear, the creditor may perform, and the debtor may request performance at any time, provided that the other party shall be given the time required for preparation.
（四）履行期限不明确的，债务人可以随时履行，债权人也可以随时请求履行，但是应当给对方必要的准备时间。
(5) If the method of performance is not clear, performance shall be rendered in a manner which is conducive to realizing the purpose of the contract.
（五）履行方式不明确的，按照有利于实现合同目的的方式履行。
(6) If the apportionment of the expenses of performance is not clear, the party performing the obligations shall bear the expenses; and any additional expenses of performance incurred by the creditor shall be borne by the creditor.
（六）履行费用的负担不明确的，由履行义务一方负担；因债权人原因增加的履行费用，由债权人负担。
Article 512 Where the subject matter of an electronic contract entered into through an information network such as the Internet is to deliver goods, and the delivery is made by means of express shipping service, the time of delivery shall be the time when the consignee acknowledges receipt. If the subject matter of an electronic contract is to provide services, the time of providing services shall be the time specified in the generated electronic document or paper document; or if the said document specifies no time, or the specified time is inconsistent with the time of actually providing the services, the time of actually providing the services shall prevail.
第五百一十二条 通过互联网等信息网络订立的电子合同的标的为交付商品并采用快递物流方式交付的，收货人的签收时间为交付时间。电子合同的标的为提供服务的，生成的电子凭证或者实物凭证中载明的时间为提供服务时间；前述凭证没有载明时间或者载明时间与实际提供服务时间不一致的，以实际提供服务的时间为准。
If the subject matter of an electronic contract is delivered by means of online transmission, the time of delivery shall be the time when the subject matter of the contract enters the specific system designated by the other party and becomes susceptible to search and identification.
电子合同的标的物为采用在线传输方式交付的，合同标的物进入对方当事人指定的特定系统且能够检索识别的时间为交付时间。
If the parties to an electronic contract otherwise agree on the method and time of delivering goods or providing services, such agreement shall prevail.
电子合同当事人对交付商品或者提供服务的方式、时间另有约定的，按照其约定。
Article 513 Where the government-fixed price or government-directed price is followed in a contract, if the said price is adjusted within the time limit for delivery as stipulated in the contract, the payment shall be calculated according to the price at the time of delivery. Where a party delays in delivering the subject matter, the original price shall be adopted if the price rises; and the new price shall be adopted if the price falls. Where a party delays in taking delivery of the subject matter or making payment, the new price shall be adopted if the price rises, and the original price shall be adopted if the price falls.
第五百一十三条 执行政府定价或者政府指导价的，在合同约定的交付期限内政府价格调整时，按照交付时的价格计价。逾期交付标的物的，遇价格上涨时，按照原价格执行；价格下降时，按照新价格执行。逾期提取标的物或者逾期付款的，遇价格上涨时，按照新价格执行；价格下降时，按照原价格执行。
Article 514 For an obligation to pay money, the creditor may request the debtor to pay in legal tender in the place of actual performance, unless otherwise provided by law or agreed by the parties.
第五百一十四条 以支付金钱为内容的债，除法律另有规定或者当事人另有约定外，债权人可以请求债务人以实际履行地的法定货币履行。
Article 515 Where an obligation has multiple subject matters, only one of which the debtor is required to perform, the debtor shall have the choice, unless otherwise provided by law, the parties, or transaction practices.
第五百一十五条 标的有多项而债务人只需履行其中一项的，债务人享有选择权；但是，法律另有规定、当事人另有约定或者另有交易习惯的除外。
If the party having the choice fails to exercise the choice within the agreed time limit or the time limit for performance, and fails to do so within a reasonable time limit after a demand, the choice shall pass to the other party.
享有选择权的当事人在约定期限内或者履行期限届满未作选择，经催告后在合理期限内仍未选择的，选择权转移至对方。