常见的合同划分与种类合同可有下列不同的标准划分:oral/parolecontractandwrittencontract(口头合同与书面合同)consensualcontractandrealcontract(诺成合同与实践合同)formalcontractandinformalcontract(要式合同与不要式合)unilateralcontractandbilateralcontract(单务合同与双务合同)principalcontractandaccessorycontract(主合同与从合同)causativecontractandnon-causativecontract(要因合同与不要因合同)commutativecontractandindependentcontract(可替换合同与独立合同)expresscontractandimpliedcontract(明示合同与隐含合同)divisiblecontractandindivisiblecontract(可分合同与不可分合同)entirecontractandseverablecontract(不可分合同与可分合同)executedcontractandexecutorycontract(已履行的合同与待履行的合同)gratuitouscontractandonerouscontract(无偿合同与有偿合同)certaincontractandhazardouscontract(确定合同与射幸合同)simplecontractandcontractunderseal(盖印合同与非盖印合同)jointandseveralcontract(连带合同)conditionalcontract(附条件合同)constructivecontract(推定合同)investmentcontract(投资合同)ope