21. It was a shame for me to say it, so I told a lie when ______ at the meeting by my boss.
A. questioning B. have questioned
C. questioned D. to be questioned
【解析】选C。考查状语从句省略。句意为：对我来说讲那件事很丢人，因此在会议上当老板询问我的时候我撒了谎。由于主从句的主语一致，在这里用了省略形式，when_____ at the meeting by my boss的完整形式是when I was questioned at the meeting by my boss。又因为I与question之间为动宾关系。故选C。
