The new colleague __________ to have worked in several big corporations before he joined our company.

【译文】那位新同事声称，在加入我们公司之前，他曾经在好几家大公司工作过。
【解析】动词的含义与用法。claim后接不定式表示“声称”，不定式中的动作如在claim之前发生则应用不定式完成式，如：He claimed to be the son of a well．known businessman．(他声称自己是一个知名商人的儿子。)He claimed to have discovered a new planet．(他声称发现了一个新的星球。)confess表示“承认、坦白”，可用于confess to sth．／doing sth．结构，如：He confessed to his crime．(他坦白了自己的罪行。)declare表示“宣布，声明”，后面一般接名词或that从句，不接不定式，如：He declared that he didn’t want to see her again．(他宣称他不想再见她了。)confirm表示“确认，证实”，后面一般也接名词或that从句．不接不定式。如：The plan was finally confirmed by the government．(政府最终证实了这个计划。)因此C为正确选项。