单选题 The professor, ______ as a splendid speaker, was warmly received by the students.
A) known B) to be known C) knowing D) having known

【正确答案】 A

【答案解析】C和D两项是主动形式，不合题意。B项是将来时态的被动态，不合时态的要求。只有A项正确，教授“被认为是……”。句意为：那位被认为是一个优秀的演讲者的教授受到学生们的热烈欢迎。