三精考点之九年级英语最易错考点系列：1.it代替动词不定式做形式主语

最易错考点系列 一 it代替动词不定式做形式主语 [来源:学科网ZXXK] ★ ○○○○ 句型It is +形容词+to do sth中的it做形式主语，真正的主语是后面的动词不定式短语。在该句型中可以在形容词后添加介词短语for、of sb，但是意义不同。1）It is +形容词+ for sb to do sth,意为“对于某人来说做某事是……”，句中的形容词经常是表示事物客观情况的形容词，如：easy，hard，important等。 2）It is +形容词+ of sb to do sth中的形容词经常表示人物的性格品质，如：kind，nice，clever等。意为“做某事你是……” It is+adj.+of sb. +to do sth中的adj.跟sb.有关,这个adj.是用来形容sb.的,表示某人这么做真是太adj.了．你会发现在这个句型中你把sb.和adj.提出来可以造个句sb. is(are) adj.如It‘s very kind of you to help me.把里面的sb.和adj.提出来可以发现you are kind是说得通的.而It is +adj.+for sb.+to do sth表示做某事对某人来说很adj.这里的adj.是do sth.的属性里面的sb.跟adj.没有直接联系如It‘s difficult for you to deal with the problem.你就不能说you are difficult了吧。这就是怎么决定句子中的介词用of还是用for的方法[来源:学科网ZXXK] 1.----Can he work out the maths problem? ----I think _____ hard for him to work it out.[来源:学科网] A. it’s B. that’s C. this is D. they’re 【易错刨析】容易误选的是BC，that和this是代词，用来指上文提到的事情时，可用this 或 that，但是若要指下文叙述的事情，通常要用 this：She married Jim, and this [that] surprised me. 她嫁给了吉姆，这使我感到很吃惊。  　　I want to know this: Is he healthy? 我想知道这一点：他是否很健康。 在打电话时，通常用 this 指自己，用that指对方：Hello. This is Jim. Is that John? 喂，我是吉姆，你是约翰吗?  this或that不能作形式主语或形式宾语。这里是it代替for him to work it out.不定式作形式宾语。 [来源:学科网] 1. His friends found to tell him everything that had happened. A. it necessary B. that necessary C. it is necessary D. necessary 2. To work out this problem is easy for me (同义句) 3. It’s too hard ___________ explain.[来源:Zxxk.Com] A. on B. with C. in D. to 每道试题20分，总计100分 1. ---Jim found _________ easy to remember all the English words. ---_________ good news it is! A. it; What B. it; How C. that; What D. its; What a 2. _________________ is important _________________ us to do morning exercises every day. A. That；for B. It；for C. This；of D. It；of 3. We all found to play the game. A. that interested B. this interesting C. it interesting D. it’s interesting ___________________________________