Yes,I bought you a pen.的问句！跪求！！！~

Did you buy a pen for me ?
相信我,肯定对!!

一楼，did I，你当自问自答吗
二楼，不够简洁
三楼，TOM哪里was mentioned？

Yes,I bought you a pen
问句是
Did you buy me a pen?
这里考察是buy的2种用法，buy somebody sth,buy sth for somebody

意思是：“是的，我给你买了一支笔。”
问题可以是“你去文具店了吗？”（Did you go to the stationery store?)

Did I buy you a pen?

tom said you bought apen for me ,is it ture?