if从句中should，主句是陈述句语气和祈使句语气就可以知道是if从句真实条件句

if从句中should，主句中含有谓语动词would/should/could/should + to do/to have done/to be doing.主句是虚拟语气，可以知道是if从句虚拟条件句。

我的疑问1：真实条件句中，if从句中的should怎么理解，这里should是理解为情态意义比如意愿？还是表示非情态意义表示委婉口气的？

虚拟条件句中的should是理解为情态意义比如意愿？还是理解非情态意义为语气标记，“协助”主动词传达非真实意义？还是表示非情态意义表示委婉口气的？

原文：从句过去(完成)时与含有would表示虚拟语气的区别 - 柯帕斯英语网 (cpsenglish.com)

If从句中的would，如果主句中含情态助动词过去时would/should/could/might，那么if从句是不是虚拟语气看语境

我的疑问2：同上

新编高级英语语法章振邦P174

原文：

第四, should +不定式用于某些表示忧虑,欢欣、不快.惊讶﹑奇怪等感情色彩的句子结构中。1这里的 should 相当于汉语的“竟然,居然.怎么会”等概念。例如:

lt's disgraceful（丢脸,不光彩) that he should act like that.

It's unthinkable that he should be so foolish.

lt 's good that somebody should have imaginations like that. lt was natural that he should feel hurt（感觉不快).

lt is awkward that he should be late.

He was disappointed that the boy should behave like that.

She was alarmed that her children should be so terribly spoilt(宠坏)

They were sorely distressed(悲痛) that their motherland should be in such greatdanger.

l am sorry that he should come so late.

l am surprised that anyone of your intelligence should be so foolish as to believe this.

They were amazed that she should have done so much in so short a time.

It 's really surprising that the weather should have kept dry for such a long time.

lt is impossible that she should have done anything like that.

It 's a pity that he should leave so soon.

It 's a shame(真不应该) that she should behave like that.lt worries me that the girl should be lazy.

lt grieves/ pains me(使我痛心) to see that he should act / should have acted so foolishly.It"s unbelievable that he should be working so hard.

上述结构所表示的时间关系是: "should +不定式进行体”表示现在时间; " should+不定式完成体”表示过去时间; "should +不定式一般形式”表示现在时间或过去时间。例如:

lt worries me that you should be looking ( = are looking ) so tired.

l am sorry that he should have been overlooked ( = has been/ was overlooked ) .

lt 's lucky that the weather should be ( = is/ was ) so fine.

不论采用should +不定式一般形式或进行体形式还是采用should +不定式完成体，其所表示的动作或状态无疑是一种事实情况,这种事实情况反映在说话人心目中引起欣慰,遗憾﹑惊奇,怀疑等等感情色彩。也正因上述动词形式指的是事实情况,因此也可以用现在时,过去时或现在完成体等表示,不同的是,后者不具有 should +不定式那样的感情色彩。

我的理解1：should +不定式用于某些表示忧虑,欢欣、不快.惊讶﹑奇怪等感情色彩的句子结构中，我认为后面的that从句是虚拟句，因为毕竟表示现实与心中想的事实想法。

我的理解2："should +不定式”与“should+不定式完成体”表示过去时间两者区别should+不定式完成体相对于谓语时间中间间隔时间较久或者中间有好几个动作。