在定语从句中只有which前面可以加介词,而what 和that前面不能加介词吗?

what 不可以引导定语从句,它不是关系词.that 不可以
指人用whom,指物用whichthat 从句不可以作介词宾语（ in, except 除外）which, what, who, whose 等引出的从句都可以作介词宾语1 那在定语从句中that可以做介词宾语吗？请举例 如果介词不前置， 可以。This is the book that I am after2 在宾语从句中which, what, who, whose 可以做介词宾语 能否举个例子？可以！Please give me some advice on how I can improve my English。I am aware od what he is doing.3 那在定语从句中which, what, who, whose 等可以做介词宾语吗？没有what可引导定语从句中的， 它不是关系词whose 是作定语的which 可以。 who在口语中可以， 毕竟它是主格，不是宾格The chair which he is sitting on is very beautiful