【题目】I regret ______ to come to your birthday party yesterday.
A. to be unable B. not to be able
C. being unable D. being not able
在线课程【答案】C
【解析】
考查固定结构。本题采用的句型为regret doing sth.：遗憾（后悔）作某事；还用到了be able to do sth的否定句be unable to do sth.未能作某事。句意：我很遗憾昨天没能参加你的生日会。故选C。