The bed wood three separate parts.
A. is made from; is made up of
B. made by; is made with
C. made of; is made of
D. is made up of; is made by
网友回答
A. is made from; is made up of
B. made by; is made with
(答案→)C. made of; is made of
D. is made up of; is made by
解析：区别be made of 与be made up of。前者意为“用……制成的”；后者是“由……组合而成”。从句子结构分析，名词bed后的是定语，应用过去分词短语，句子的主谓是被动关系，意为“由三个部分组成”，故用is made up of。