Samuel Clemens Mark Twain because a famous American writer.A. was known asB. known asC.

问题补充：

Samuel Clemens, Mark Twain, because a famous American writer.

A. was known as

B. known as

C. was known for

D. known for

答案：

A. was known as

(答案→)B. known as

C. was known for

D. known for

解析：考查非谓语动词。Be known as作为某种人物出名；known for以某事出名。句意：克莱门斯，以马克吐温的身份著名，成为一个著名的小说家。过去分词表示被动的发生过的动作，前面不用助动词，故选B。