He did not regret saying what he did but felt that he _____ it differently. [ ]

A. could express

B. would express

C. could have expressed

D. must have expressed

相对购买力平价指出汇率的预期变动率是与本国和外国（）差异成比例。

A.通货膨胀率

B.价格水平

C.利率

D.股指