____ you think he ____back by dinner time?

题目

____ you think he ____back by dinner time?
选项A为Do; have come 是错误的；
但我们老师讲若have改成be就正确,为什么?

答案

要改成will be吧.1,Have本来就不能用在第三人称.2.时态不对.Have come是现在完成时 will be是将来时