英语里有些形容词在意义上与情态或意愿有关，如imperative(非常必要的)、impossible, natural, necessary, obligatory(必须的), preferable(更好的), proper, sad, strange, surprising, vital(至关重要的)、advisable, appropriate（适当的）, crucial, desirable（好的，所希望的）, essential, fitting,等。当用先行词it充当主语而用它们充当表语时，则that从句的谓语动词用现在时虚拟式（在美国英语里），或者用should+动词原形（在英国英语里）；句型结构如下：
it is（was） + adj + that +sb + （should）do/be + sth
该结构中的主语从句表示说话人的意愿或主观态度，结构中的形容词用来表现说者的意愿趋向, 从句中的动词应用现在时虚拟式。请看经典例句如：
It is absolutely imperative that we finish by next week.
我们的当务之急是必须于下周完成。
It was imperative that he act as naturally as possible...
最重要的是他要做到尽可能自然。
It's imperative that we get there on time.
我们的当务之急是必须准时到达那里。
Seeing as how we got on so well together, it just seemed natural that we should hook up.
既然处得这么好，似乎我们理所当然应该搭档。
It is only natural that he should resent you
他怨恨你是很自然的事。
It's necessary that you should be present at the meeting.
你有必要参加会议。
It is important and necessary that we should master a foreign language.
掌握一门外语对我们来说是重要的和必要的。
It is necessary that food be sent to them at once.
有必要把食物立即给他们送去。
It is important that he should attend every day.
他每天都要出席，这很重要。
It is proper that you should ask your father.
你当然应该问你的父亲。
It's only right and proper that we should pay taxes to the state.
给国家纳税是天经地义的事。
It is sad that a major company should try to gain from other people's suffering.
一家大公司竟然试图发别人的苦难财，真是令人悲哀。
It is sad that a major company should try to gain from other people's suffering.
一家大公司竟然试图发别人的苦难财，真是令人悲哀。
It was sad that his international career should end in such anticlimax.
令人悲哀的是，他的国际职业生涯竟如此惨淡收场。
It's strange that it should be so hot today.
很奇怪，今天竟会这么热。
It is strange that he ( should) have so many friends.
太奇怪了，他有那么多的朋友。
It is vital that you keep accurate records when you are self-employed.
干个体的要准确记录账目，这十分重要。
It was vital that the elections should be free of coercion or intimidation.
选举中不应有强迫或恐吓行为，这一点至关重要。
It is vital that we act to stop the destruction of the rainforests.
至关紧要的是，我们应当采取行动制止破坏雨林。
Javed Khan, of children's charity Barnardo's, said: ＂ It's vital that new compulsory age-appropriate relationship and sex education lessons in England should help equip children to deal with the growing demands of social media ．＂
儿童慈善机构Barnardo的贾维·德汗说："在英国,新的适龄义务关系和性教育课程应该有助于培养儿童应对社交媒体日益增长的需求,这一点至关重要。"
高考真题- 2018 江苏 阅读D
It is surprising that they should come so early.
他们那么早来令人惊奇。
It is surprising that Mary should win the first place.
玛丽得了第一，这事可真够令人吃惊的。
It is surprising that you should learn English so well in such a short time.
你在这样短的时间内把英语学得这么好，真令人吃惊！
It is advisable that we ( should) stay at home instead of going to the movie.
我们还是不去看电影，呆在家里好。
It is appropriate that Irish names dominate the list
名单上大部分是爱尔兰名字，这没什么不合适的。
It is appropriate that he should get the post.
由他担任这一职务是恰当的。
It is crucial that we get this right.
我们把这个问题弄明白是极其重要的。
It is desirable that interest rates (should ) be reduced.
利率下调是可取的。
It is highly desirable that a new chairman be appointed.
任命一个新的主席相当有必要。
It is essential that we present a united front.
至关重要的是我们要表现得团结一致。
It is essential that we tackle this thorny problem.
我们很有必要处理这个棘手问题。
It is fitting that the new centre for European studies should be in a university that teaches every European language.
新的欧洲研究中心应设在教授所有欧洲语言的大学里才合适。
It is fitting that we should remember him on his birthday.
我们在他的生日向他祝贺是合适的。
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