Someone must have taken it away this morning,___?为什么填didn't he Thankyou!

问题描述:

Someone must have taken it away this morning,___?为什么填didn't he Thankyou!

前肯定,后否定,这里没有戏词be所以用do not\ does not 或did not,根据时态(taken)确定用
过去时态did not ,Someone用单三形式,所以用he

因为这是表示推测的,推测的内容是过去的——即今早,
所以,要由意思,对过去时进行反问.
这种对过去情况表示推测的句子,有很多.
He must have left yesterday, didn't he?
他昨天一定走了,是吗?
It must have snowed yesterday, didn't it?
昨天一定下过雪,是吗?
You must have arrived yesterday, didn't you?
你一定是昨天到的,对吧?