定语从句）区分用who还是用whom,是看代替的先行词在主句中作说明成分还是关系词在从句中充当的成分?

定语从句中：He is the man who likes classical music .(在从句中做主语）
He is the man whom we like very much.（在从句中做宾语）
宾语从句中：I don't know who did it in such a foolish way.（在从句中做主语）
I don't know whom he had write the letter.(在从句中做宾语）
所以说,与主句实在没有什么关系.