这个加不加be ,要具体情况具体分析
当只是表一个被动句的时候，加be 动词，比如
the tool is made by metal
几乎等于be made of
the tool is made by you
如果一个句子，已经出现了动词，那么be made of/by 只能做为过去分词做定语，不能加be,以免和谓语动词重复，比如
i have a tool made by you
= i have a tool (which is )made by you
类比的简单句子（你肯定见到的）
i have a friend called mike
my friend is called mike
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