一直都很困惑比如这题，it✀s high time we ___ a rest. A have B had C are having Dshould have

你好

It is high/about time that 正是干……的时候了high/about 只是对time 强调
从句谓语动词要用过去式或用should加动词原形，但should不可省略。
例如

It is time that the children went to bed.

It is high time that the children should go to bed.

综上所诉, 上题答案为B和D

若有疑问及时追问，如满意请点击下面的“选为满意答案”按钮，谢谢！O(∩_∩)O

这是虚拟语气，表示：“早该做某事了”，后面可接动词过去式或should+动词原形，比如下面两句都是对的

It is time that I went to pick up my daughter at school.

t is high time you should go to work.

B/D
你的理解对的。
在“It is（high/about）time+that”引导的从句中，从句的主谓语用一般过去时，也可以用should+动词原形，should不予省略。
It is high (about)time that we left/should leave

It is high time 后面要用虚拟式，是 do的过去式，did,所以这道题 要选 B.
现在必须做什么了，否则就。。。，隐含一种假设。
It is suggested that...这个句子才用should 加动原，始be型虚拟式。

有两个答案。填should+动词原形 或者直接填动词过去式。