Mary asked Jack ,"have youpacked your things?"为什么把have变成had
问题描述：
Mary asked Jack ,"have youpacked your things?"
为什么把have变成had
答
玛丽问杰克：“你的东西都打包好了吗？”
答
Mary askd Jack if he had packed his things.
答
Mary asked Jack to pack his things.( ask sb.to do sth.叫某人做某事）
Mary asked Jack if he had packed his things.宾语从句
答
Mary asked Jack whether he had packed his things.