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第四百七十六条 要约可以撤销，但是有下列情形之一的除外：
Article 476
An offer may be revoked, unless under either of the following circumstances:
（一）要约人以确定承诺期限或者其他形式明示要约不可撤销；
(1) the offeror has explicitly indicated that the offer is irrevocable by
specifying a time limit for acceptance or in any other manner; or
（二）受要约人有理由认为要约是不可撤销的，并已经为履行合同做了合理准备工作。
(2) the offeree has reasons to believe that the offer is irrevocable and has
made reasonable preparations for performing the contract.
第四百七十七条 撤销要约的意思表示以对话方式作出的，该意思表示的内容应当在受要约人作出承诺之前为受要约人所知道；撤销要约的意思表示以非对话方式作出的，应当在受要约人作出承诺之前到达受要约人。
Article 477
Where an expression of intent to revoke an offer is made through real-time
communication, the content of such expression of intent shall be known to the
offeree before the offeree makes an acceptance; where an expression of intent to
revoke an offer is not made through real-time communication, it shall reach the
offeree before the offeree makes an acceptance.
第四百七十八条 有下列情形之一的，要约失效：
Article 478
An offer becomes invalid under any of the following circumstances:
（一）要约被拒绝；
(1) the offer is rejected;
（二）要约被依法撤销；
(2) the offer is revoked in accordance with law;
（三）承诺期限届满，受要约人未作出承诺；
(3) the offeree makes no acceptance prior to expiration of the time limit for
acceptance; or
（四）受要约人对要约的内容作出实质性变更。
(4) the offeree materially alters the content of the offer.
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