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：根据句意及句子结构可知，句子的主语Dr，Lillian Glass实际上就是选项动词的主语，相当于As he is known as...引导的原因状语从句，为被动结构，故选过去分词known。