他问我英语

第一个空是if 第二个是 are

He asked me what I did yesterday

He asked me what did i do yesterday afternoon

He ask me what i did yesterday afternoon.

what did you do yesterday afternoon

if 或whether，had been【人教版初中英语书上有：主句是过去时，从句要用过去完成时】

He asked me what I did yesterday afternoon.