初二it做形式主语讲解.docx

“It”形式主语Examples:1. Its necessary for the young to master two foreign language2. It is no use arguing about the matter with him. 3. Its a pity that you fail the exam.It 用作形式主语当不定式（短语）、动名词（短语）或从句在某个句子中作主语时，为保持句子结构前后平衡，避免头重脚轻，因此常用it作形式主语置于句首，而将真正的主语放在句尾。此时it只起先行引导作用，本身无词义。一、 代替动词不定式做主语拒绝是令人遗憾的。Its a pity to refuse.记住这点是很重要的。Its very important to remember this point.1. It + be + 形容词 + for sb + to do sth 这类句型常用形容词(通常为描述事件的形容词)easy, difficult, hard, important, possible，wise, necessary, impossible, likely, obvious, useful, 等作表语，有时候为了强调不定式动作的执行者，常在不定式前加for sb，译为“对某人来说做某事怎么样” Its necessary for the young to master two foreign languages. It is unwise to give the children whatever they want.2. It + be + 形容词 + of sb. + to do sth这类形容词常是表示心理品质,性格特征的形容词，如：kind, nice stupid, clever, foolish, polite, impolite, silly, selfish, considerate等。某人和这些形容词可以构成主系表结构。Its very kind of you to help me with the work.=You are kind to help me with the work.Its foolish of you to drive a car after drinking. =You are foolish to drive a car after drinking.3. It + be +名词词组 + to do sth It is not a good habit to stay up too late.4. It takes/took sb +some time/ money to do sth做某事花了某人多长时间或多少钱It took the workers almost three years to finish building the dam.It will take a whole day to get to the top of the mountain on foot.二、 it代替动名词做形式主语It is no good use crying over spilt milk. (覆水难收)It is no use casting pearls before swine. (不要明珠暗投，对牛弹琴)It + be + 名词或形容词 + 动名词这类名词和形容词常常是：good, no good, no use, a waste of, useless, senseless等Its a waste of time talking to her any more。It is no use arguing about the matter with him.三、 it代替从句做主语1. it + be + 名词词组 + 主语从句这类名词有：a fact, a pity, a shame, an honor, a question, a surprise.Its a pity that you lose your money2. it + 不及物动词+ that(as if )+ 从句这类不及物动词有：look, seem, appear, happen, occur,It seems that he does not tell the truth.It occurs to me that I forgot to lock the door!我突然想起我忘记锁门了3. it + be + adj + that从句It is necessary/impossible/important/natural that sb. (should) do sth. Its important that we (should) keep the balance of nature4. it + be + -ed(过去分词)+ that 从句 it is said that . 据说.it is reported that 据报道it is supposed that 据推测it is well known that 众所周知it is generally considered that 普遍认为it is suggested that 有人建议实战演练： 1. It is generally considered unwise to give_ a child he or she wants. A. however B. whatever C. whichever D. whenever 2. In fact_is a hard job for the police to keep order in an important football match. A. this B. that C. there D. it 3. _is a fact that English is being accepted as an international language. A. There B. This C. That D. It 4. Is _ necessary to take off our shoes when we enter the lab? A. everyone B. this C. her D. it 5. _ will take you a lot of time to find him in the crowd. A. It B. I C. We D. They 6. It is no use his _ there, the situation is hopeless now. A. to go B. to be going C. going D. having gone 7. It is never too late to learn, _? A. is it B. isnt it C. does it D. doesnt it 8. _ is known to all that Shenzhou VI Launched Successfully. A. As B. What C. It D. That 9. _ is reported in the newspaper, the Earthquake in east Chinas Jiangxi Province killed 13 people A. It B. As C. That D. What 10. _ certain that his invention will make peoples life convenient. A. Thats B. This is C. Its D. Whats 11. _ that there is another football match on the air this evening. A. It says B. It was said C. It is s