In January 2010 Ami took over an old warehouse with the intention of opening an art gallery. As the warehouse had to be converted, Ami entered into two contracts, one with Bry to do all the necessary plastering and one with Cis, who was to do all the necessary painting. Both Bry and Cis were to be paid ￡5,000. Both received initial payments of ￡1,000 and agreed to have the work completed on 31 March, as the art gallery had to be ready for its fi rst exhibition on 1 May.At the end of February, Bry told Ami that he would not complete the plastering in time unless she agreed to increase his payment by a further ￡1,000. Ami agreed to pay the increased sum in order to ensure that the job was done on time. She then thought it was only fair that she should increase the amount of money promised to Cis by the same amount.However, on completion of the work on time Ami refused to make either of the additional payments to Bry or Cis, beyond the original contractual price.Required:Advise Bry and Cis whether they have any rights in law to enforce Ami’s promise to pay them an extra ￡1,000. (10 marks)

哪项肺功能对阻塞性肺气肿的诊断最有价值（）

A.潮气量

B.肺活量

C.PaO

D.残气量／肺总量的百分比测定

E.弥散功能