在有情态动词的虚拟语气条件句中，只有should可以倒装。倒装时，把should移至句首，去掉if。例如：
If you should prepare to go there ,I should go with you.
= Should you prepare to go there ，I should go with you. 如果你准备去那里的话，我就和你一块去。
若虚拟语气条件句中有动词were,should或had, 都可以把这三个词放在主语之前,去掉if,变成倒装句。例如：
If I were a bird,I would fly.
=Were I a bird,I would fly.如果我是一只小鸟，我就会飞翔。
If we were confident ,we would be able to overe all difficulties.
= Were we confident ,we would be able to overe all difficulties.如果我们有信心，就能够克服所有的困难。
If he should agree to go there, we would send him there.
=Should he agree to go there, we would send him there. 要是他答应去的话，我们就派他去。
If you had e，we wouldn't have been so busy.
= Had you e yesterday, we wouldn't have been so busy.如果你昨天来的话，我们就不会那么忙了。
If I had enough time, I would go to his help.
= Had I enough time, I would go to his help.如果我有足够的时间，就去帮助他。
此句考查虚拟语气，意为：Smith已经有预订。如果他改变主意，可以取消。
前一句是描述过去的事实，后一句是描述现在还没发生，但是假设可能会发生的情况，假设即虚拟。我们从句意以及句子所用时态判断其为对将来的虚拟，可以由三种表达：
If he should change his mind,----
If he changed his mind,----
If he were to change his mind,----
以上三种中，1和3可以进行倒装，原则是删掉if，助动词/be动词/情态动词提前，放在句首：
1. Should he change his mind,----（正是你的疑问）
3. Were he to change his mind,----
should用在if引导的条件从句，可以表示事情听起来可能性很小，但是也并非完全没可能。相当于 万一
It's time that he___ what he should choose as his major
A reconsiders B reconsideredC would reconsider D has reconsidered
为什么选B
--你要掌握虚拟语气的一些特殊结构。如本题的It's (high)time that *** . did sth.[后面动词用过去式]
If I ___have tens of thousands of yuan in future ,I would help my home village build a new school.为什么填should
这也是虚拟语气的固定结构，与将来相反的假设条件从句可用“ 过去式”、“should +动词原形”或“ were to +动词原形”
None was so deaf as those who___hear.
Awon't Bcan't C shouldn'tD may not
为什么填won't
这是一句英语习语，"won't"表示"不愿意"：
None was so deaf as those who won't hear.
不愿意听（别人意见等）的人是最聋的。
DACCBDDB
suggest 这个单词在翻译的时候有两种：
1，建议
2.暗示，表明
当在句子中翻译为建议时，后面的从句应该使用should+动词原形的虚拟语气。而且should是可以省略的。
当在句子中翻译为暗示，表明时，后面也就不再虚拟了。 题中，句子翻译为：他的口音暗示着他来自于美国。 在翻译的时候，suggest呗理解为暗示，故而不虚拟。而且从句中的主语的第三人称单数，故而选择es, 希望采纳。谢谢
就是使用加强语气的
1.D
2.A
3.C
你有正确答案吗？我不保证对的。
不过，虚拟语气说简单点，就是把句子应有的时态向过去推一个时态（这只是有些投机取巧的窍门）
每个情态动词还是有它自己的意思的，would表意愿，should表应该，could表能力，might表可能性。
按照句子的意思用这几个次往里套，哪个更符合逻辑就选哪个就行了。
这个回答满意吗？如果还有什么要求就用“问题补充”吧！我会再来的！
这个不一定是的。它可以有两种情况的。
情态动词+have done:第一，表推测;第二，表虚拟。
1.edn't /shouldn't +have done 表对过去的推测，译为“本不需要、本不应该做....”
2.can't have done 表对现在的推测。译为“不可能....”
3.mustn't have done 表对过去的推测。译为“一定不会...”
4.couldn't have done 表推测是和2一样。它也可表虚拟，译为“本不可能...”
嘿嘿，我们老师今天上午刚讲的，应该没错。你也可以再咨询一下你们的老师。
1.没看懂 后半句好象不全
2.在mary真正来了之前 谁也不能肯定她什么时候来 搞不好不来了 A和B明显不对 D太过肯定
3.may
4.现在分词表示主语的性质 过去分词表示主语的状态或者感受 如the book is interesting 和 I'm interested in ...
5.不懂 can't 应该可以
6.同位语从句 the fact that ... fact是现在很忙 是事实 不用虚拟