can you tell me ( )the train was invented.是who 还是when I need reason

问题描述:

can you tell me ( )the train was invented.
是who 还是when
I need reason

when

when
这句话是用when引导的时间状语从句,意思是 你能告诉我火车是谁发明的吗?
如果用who的话应该这么说 can you tell me who invented the train