He is famous the field of biology, but he is more known an environmentalist..
A. for, for
B. in, for
C. in, as
D. in, as
网友回答
A. for, for
B. in, for
(答案→)C. in, as
D. in, as
解析：考查固定搭配。固定搭配be famous for…因为…而出名；be famous in…在…方面出名；be known as…作为…而出名；句意：在生物学领域他很出名；但是作为一名环境保护主义者，他更出名。故C正确。