1、常用it作形式主语的句型结构◇ It+be+形容词+that-从句可用于此句型的形容词有:wonderful, true，good，right，wrong，（un）important，useless，surprising，clear，unusual，lucky，certain,necessary等。 如：①It is quite certain thathe will be at the meeting.②Itissurprisingthathecamelatetoschoolthismorning.
2、③It is important that we (should) study hard注意:该句型中的形容词是（un）important,necessary等时，从句应为(should)+动词原形。◇ It+be+-ed分词+that-从句 适用该句型的过去分词主要有:said, reported, announced, hoped, thought，told，believed，expected，decided，suggested, known等。如： ①It is
3、hoped that one day they will have enough animals to set them free ②Itiswellknownthattheearthgoesaroundthesun. ③Itissuggestedthatthesportsmeeting(should)beputoffuntilnextweek.注意:该句型的过去分词是suggested时，从句应为(should)+动词原形。◇ It+be+名词+that-从句
4、 适用该句型的名词（词组）有:a pity，an honor，a good thing，a fact，a surprise，good news,one’sduty等。 如：①It is a pity (that) you missed the sports meeting last week. ②It is a fact that English is being accepted as an international language. ◇ It ＋seem／ appear／ h
5、appen的适当形式＋that从句。该句型常可以转换成含不定式的简单句。如：①It seems that there is a big waste pipe coming down from the town. →There seems to be a big waste pipe coming down from the town.②He appeared tobecalm, but inside his heart was beating wildly with fear. →It appeared th
6、at he was calm, but inside his heart was beating wildly with fear.◇ It doesn't matter (It’snowonder;Itdoesn’tmakemuchdifference等) ＋ when/ where/ which/ whether 等从句。 如：①Does itmatter if he can't finish the job on time?②They are all classmates.Itis no wond
7、er they should help each other with their studies.◇ It + be + adj./ n. (for sb. / of sb.) + to do sth. 该句型中的形容词通常是表示事物的特点或特征的如difficult，hard，easy，impossible，necessary，important等，此时用for；或表示人的性格特征或特点的如nice，good，bad，kind，silly，foolish，wise，clever， carele
