问题补充:
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
答案:
A. could express
B. would express
(答案→)C. could have expressed
D. must have expressed
解析:掌握情态动词的完成结构的用法是解此题的关键,could express过去能够表达;would express(过去)将要表达;could have expressed本来能够表达;must have expressed(表推测)肯定能表达。