Much disappointed as he is in the job interview, he still keeps his confidence.
A. failed
B. to have failed
C. having failed
D. Failing
网友回答
A. failed
(答案→)B. to have failed
C. having failed
D. Failing
解析：考查不定式的用法：这句话是as的倒装句，还原后是Though he is much disappointed ,这时可以看出是句型：Sb/sth is +adj +to do这个句型，这里的不定式是主动表被动，而且如果不定式的动作在主句的动作之前发生，用不定式的完成式，句意：虽然他在工作面试中失败很失望，但他还是保持自信。选B。