一句话的时态

题目

一句话的时态
下面是新目标英语9年级Review of units 11-15 2a,2b Conversation 3里的,问题我在括号里写出来了,请帮忙分析,
-We have to leave in half an hour.Is everything ready for the trip?
-I don't know.
-Well,have you packed the travel guidebook?(问句用的现在完成时)
-Yes,I did.（回答用的一般过去式,为什么不用yes,I have.） Oh!But I forgot the map.
.

答案

Gramatically it should be "yes,I have" but in spoken language we might say "yes,I did" in reply to this question.