as the “First Lady of Speech”, Dr Lillian Glass is recognized as one of the world’s leading experts on munication skills.
A. Knowing
B. Having known
C. Known
D. To be known
网友回答
A. Knowing
B. Having known
(答案→)C. Known
D. To be known
解析： know 与Dr Lillian Glass存在被动关系，应用过去分词。故选C。