25.虚拟语气在名词性从句中的用法
1.虚拟语气在主语从句中的用法
在以it作形式主语的复合句中，主语从句常用虚拟语气来表示建议、命令、要求、主张、决定等，从句谓语动词应用“should+动词原形”的形式，should可以省略。这种复合句有以下三种常见形式：
(1)“It is/was+形容词+主语从句”句型。
常见的此类形容词有：appropriate,obligatory, advisable, essential, important, insistent, adamant(坚决的)，imperative(重要紧急的)，natural, necessary, preferable, better, desirable,urgent, compulsory(强制的)，vital，proper等。
It was adrisable that Lily (should) listen to others' advice when making a choice.
莉莉在做出选择的时候听取他人的建议是明智的。
It is very important that people (should) stay positive and confident when in difficulty.
人们处于困境中时保持乐观和自信非常重要。
It is necessary that we (should) learn to protect our privacy when surfing the Internet.
我们在上网时学会保护自己的隐私是必要的。
(2)“It is/was+名词+主语从句”句型。
作表语的名词表示建议、命令、要求、主张、计划、愿望等意义。常见的此类名词有：decision，suggestionpreference, proposal, advice, command, recommendation, desire, demand, requirement, order,necessit reguest, idea, resolution, motion, plan, wish等。
It is John's demand that the boss (should) double overtime pay.
约翰的要求是老板把加班费翻一番。
It was the old man's request that his property (should) be given to the poor after his death.
这位老人的要求是他死后将其财产捐给穷人。
(3)“It is/was+过去分词+主语从句”句型。
此类过去分词为表示建议、命令、要求等意义的动词的过去分词形式。常见的此类过去分词有：adviseddesired, demanded,ordered, requested, suggested, recommended, required, proposed,decided等。
It is demanded that the public (should) be told the whole truth about what has happened.
有人强烈要求公众应当被告知所发生事情的全部真相。
It is suggested that parents (should) spend more time with their children.
有人建议父母应该多花时间与自己的孩子们待在一起。
It is required that middle school students (should) take exercise at least one hour every day.
有人要求中学生每天至少锻炼一个小时。
2.虚拟语气在宾语从句中的用法
(1)在表示建议、命令、要求、主张等含义的动词后接的宾语从句中虚拟语气的用法。
表示建议、命令、要求、主张等含义的动词后接的宾语从句一般应用虚拟语气，即从句谓语动词应用“should+动词原形”的形式，should可以省略。常见的此类动词有：advise, ask(要求)，determine, decide, demand, command, insist(坚持，坚决要求)，propose, order, recommend(劝告，建议)，request, require, suggest,urge, prefer, desire 等。
He adrised that the doctor (should) be sent for at once.
他建议立马请医生来。
The mother demanded that her daughter (should) go home right away.
这位母亲强烈要求她的女儿立即回家。
They proposed that all the plans (should) be discussed at the meeting.
他们建议在会上讨论所有的计划。
在“It is was a pity/a shame/no wonder/amazing/surprising/astonishing/shocking/strange...+that 从句”句型以及“I am/was sorry/surprised/disappointed...+that从句”句型中，从句谓语动词一般应用“should+动词原形”的形式，此时should意为“竟然，居然”，表示说话人的惊异、懊悔、失望等情感。如：
It is a pity that Henry should make such a mistake.
亨利居然犯了这样的错误，真可惜。
It is astonishing that the neighbors should know nothing about the murder case.
令人惊讶的是邻居们竟然对这起凶杀案毫不知情。
I'm very surprised that he should learn so much in such a short time.
我很惊奇他竟然在这么短的时间内学到了这么多东西。
此类动词可记为以下口诀：一个坚持(insist)；
两个命令(order,command)；三个建议(suggest,advise，propose);
四个要求(ask,demand,request,require)。
当 suggest 和 insist不表示“建议”和“坚持，坚决要求”，而分别表示“暗示，表明”和“坚持说”时，其后的宾语从句不需要用虚拟语气，而应用陈述语气。如：
The smile on his face suggested that he agreed to this plan.他脸上的微笑表明他同意这项计划。
He insisted that he had done nothing wrong.他坚持说自己并没有做错什么。
