I can't find my pen yet;in fact,I am not sure--I could have

i could have done (what) with it 我对我的笔到底做了什麽 这里的什麽是what
而不是问把它放哪儿了所以不用where
如果是where 应该是where i could have put it之类的 句子里缺什麽 什麽可以带入到句子中 就用什麽