国际商法概念中英对照合同法合同的成立要件:通过要约和承诺达成合意(Agreement)当事人具有缔约能力(the legal capacity to contract) 存在对价( Consideration)或对价( Cause )合同形式符合法律规定具备合法性合意必须真实(Intention of parties)要约( Offer )要约人offerer 受要约人offeree 邀请邀约invitation for offer 要约的确定性definiteness 要约人受约束的意旨intention to be bound 特定人specific persons 要约的撤回withdrawal of offer 要约的撤销revocation of offer 确定的要约firm offer 要约的消灭 / 终止 termination 承诺 Acceptance 镜像规则mirror image rule 反要约counter offer 承诺生效的时间英美法:邮箱规则:mailbox rule (发出时有效,有利于受要约人,缩短要约人可撤销要约的时间)大陆法:德国、合同通则:到达生效原则receipt rule 合同的效力Validity 有效合同legal 无效合同void 可撤销合同avoidable 效力待定 / 不可强制执行的合同影响合同效力的因素:错误mistake:重大误解substantial misunderstanding 欺诈 fraud 胁迫 duress 显失公平不正当影响undue influence 不履行( non-performance)可免责的不履行excused non-performance 不可抗力force majeure/impediment beyond control: 无法控制;无法预见;无法避免;无法克服重大违