unilateral contract

A donation agreement is a kind of unilateral contract.

赠与协议是一种单务合同.

They took the unilateral decision to cancel the contract.

他们单方面决定撤消合同.

Changes clause: A clause in a contract giving a contracting officer the right to make unilateral changes to a contract, provided that the changes are within the general scope of the contract.

变更条款：合同中的一项条款，它给予签约官员单方面对合同作某些变更的权力，但这种变更仅限于合同总的范围以内。

For, only if the definition of contract base on the promise, we can explain the most three familiar contract& unilateral contract, bilateral contract and formal contract.

因为只有建立在允诺基础之上的契约概念，才能同时解释三种最为常见的合同&单边（unilateral）合同、双边（bilateral）合同和要式（formal）合同。

The first is the right to regret define. Express regret that the right to the concept of the contract after a period, in accordance with the provisions of the unilateral withdrawal of the contract without reasons, the responsibility of the rights.

首先，对后悔权加以界定，明确后悔权的概念即消费者在订立合同之后的一段时期之内，依据法律的规定单方面撤销合同而无须说明理由、承担责任的权利。