单选题 Robert is said ______ abroad, but I don't know which country he studied in. A. to have studied B. to study C. to be studying D, to have been studying
【正确答案】 A
【答案解析】[解析] 此题考查不定式的完成时。“据说他曾到国外留过学”，由studied可知“留学”这个动作已结束并发生在谓语动作is said之前，所以要用完成式。