承包商在接到业主未明确承诺对于中标通知书之前完成的业主指定工作给予合理的报酬的意向书后，应主动向业主写信。例如 Dear Sir or Madam: Re: Employer’s intention to enter into a contract with us for Good Luck Plaza Thank you for your letter of 7 May 1999 informing us of the Employer’s intention to enter into a contract with us for this project on the basis of our tender of 5 January 1999. You request us to start the access to the site in anticipation of the contract. However, before undertaking this preparatory work we would like to have an express undertaking from the Employer to reimburse the cost of any work so undertaken, together with a reasonable allowance for overhead and profit, should the contract not proceed for any reason. On receipt of this undertaking, we shall proceed immediately in accordance with your request. Yours sincerely, 3. 协议书 协议书是专门用来使合同文件正规化的书面文件。根据法律规定，协议书不是为形成合同文件所必需的。但是，在大型工程项目施工合同中，签定协议书是一种惯例。协议书实际上是合同文件的浓缩。它列出合同各组成部分的名称，简略叙述合同的重要内容，如工程内容、完工时间、误期赔偿及付款办法等；同时，也可以包括某些类似于合同条款补充和扩展的条文。 （百考试题造价师）