1、Module2 Environment problems Unit 4 Natural disasters,it 做形式主語或形式賓語,1. It 用作形式主語,當(dāng)不定式（短語）、動名詞（短語）或從句在某個句子中作主語時，為保持句子結(jié)構(gòu)前后平衡，避免頭重腳輕，因此常用it作形式主語置于句首，而將真正的主語放在句尾。此時it只起先行引導(dǎo)作用，本身無詞義。,It be +,adj n p.p,(for/of sb) to do sth 主語從句 doing sth,+,1. It+ be +adj.+主語從句 這是主語從句最常見的一種結(jié)構(gòu)。 It is uncertain whether he c

2、an come to Jennys birthday party or not.,注意：如若形容詞為 important / necessary， good/wrong natural.表達(dá)一種要求，命令或者責(zé)備時，多使用虛擬語氣（should +V).但是如果只是表示陳述一個事實(shí)而不是強(qiáng)烈的感情，完全可以用一般的陳述語氣。 不過考試建議你還是多用虛擬語氣 It is important that we (should) learn English well. It is necessary that he (should) remember these words.,2. It + be +

3、 過去分詞 + 主語從句，這類過去分詞有：announced, believed, expected, hoped, decided, reported, said, shown等， 如：It is reported that 16 people were killed in the earthquake.It is not decided who will give the operation to the patient. It is said that he has come to Beijing.,注意：如果主句中的過去分詞是表示請求，建議，命令等詞如：suggested/ order

4、ed / demanded /insisted / commanded. 等時 that后的從句要用虛擬語（should + 動詞原形），should 可以??； 常譯為，“據(jù)建議；有命令） It is suggested that the meeting ( should ) be put off. It was ordered that we ( should ) arrive there in two hours.,3. It + be + 名詞詞組 + 主語從句 這類名詞有：a fact, a pity, a shame, an honour，a question等，如： Its a p

5、ity that you missed the exciting football match. It remains a question whether he will come or not. 注意：如若表示出乎意料之意時,從句一般用虛擬語氣常譯為“竟然”。沒有這種意義時，則不用虛擬語氣。 It is a pity that such a thing ( should ) happen in your class.,4. It + 不及物動詞 + 主語從句 這類不及物動詞有：appear,seem happen，matter等。譯為好像/碰巧/如： It seemed that he d

6、idnt tell the truth. It happened that I was out when he called.,5. It + be + 形容詞 + （for sb.）+ 動詞不定式 這類句型常用形容詞easy, difficult, hard, important, possible，wise等作表語，有時候?yàn)榱藦?qiáng)調(diào)不定式動作的執(zhí)行者，常在不定式前加for sb，譯為“對某人來說做某事怎么樣”如： Its necessary for the young to master two foreign language. It is unwise to give the child

7、ren whatever they want.,6. It + be + 形容詞 + of sb. + 動詞不定式 這類形容詞常是表示心理品質(zhì),性格特征的形容詞，如：kind, nice stupid, clever, foolish, polite, impolite, silly, selfish, considerate等。某人和這些形容詞可以構(gòu)成主系表結(jié)構(gòu)。如： Its very kind of you to help me with the work. =You are kind to help me. It seemed selfish of him not to share hi

8、s dictionary with others. =He seemed selfish not to share his dictionary with others.,7. It + be +名詞詞組 + 動詞不定式，如： It is not a good habit to stay up too late.,8. It + be + 名詞或形容詞 + 動名詞， 這類名詞和形容詞常常是：good, no good, no use, a waste of, useless, senseless等，如： Its a waste of time talking to her any more.

9、It is no use arguing about the matter with him.,9. It + take ( sb. )+ 時間（金錢）+ 動詞不定式，譯為，做某事花了某人多長時間或多少錢。如： 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.,He found it difficult to stop smoking I think it best that

10、you should do more exercise. She thought it no good worrying about him,It作形式賓語 代替不定式、動詞-ing短語、或從句。,2.It 用作形式賓語,當(dāng)不定式（短語）、動名詞（短語）或從句在句子中作賓語時，為保持平衡，避免句式結(jié)構(gòu)的混亂，常用it作形式賓語，而將真正的賓語放在句尾。此時it只起引導(dǎo)作用，無意義。,S + v + it+,adj. n,(for sb) to do sth. 從句 doing sth,+, find possible S+ think + it + necessary +( for sb. )

11、 to do sth. /clause. feel important ,Sentence patterns:,形式賓語, a rule 2. S+ V + it + ones duty + ( for sb. ) to do sth. /clause an honour ,3. S + V + it + no good + doing sth. no use,完成句子,（1） They _（發(fā)覺難） to finish their work in two days. （2） We _（認(rèn)為是我們的職責(zé)） to clean our classroom every day. （3） It is

12、important _（對她來說） to cometo the party.,found it difficult,think it our duty,for her,作形式賓語( Preparatory Subject ),為了記憶方便我們把該句型總結(jié)為6123結(jié)構(gòu)。,6指主句中常用的動詞：think,believe,make,find, consider,feel； 1指的是形式賓語it； 2指的是賓補(bǔ)的兩種形式：形容詞或名詞； 3指的是真正賓語的三種形式：不定式短語，動名詞短語 或從句。,We think it our duty to clean our classroom every

13、day. He felt it important learning English well. They found it difficult that they would finish their work in two days.,4.It 作形式賓語的特殊用法,1. 某些表示“喜、怒、哀、樂”的動詞，如like, enjoy, love, hate, dislike, appreciate等 后往往不能直接接賓語從句；必須先由it擔(dān)任形式賓語,再接從句.,We would much appreciate it if you could do us that favour. 要是你們能

14、幫我們這個忙，我們將非常感激。 Id prefer it if I didnt have to finish the work. 要是我不必完成那項(xiàng)工作，那就太好了。,2.某些含有介詞的動詞短語如see to, depend on, answer for, rely on, insist on, look to, stick to 等結(jié)構(gòu)中往往不能直接接賓語從句；必須先由it擔(dān)任形式賓語,再接從句.,Ill see to it that everything is ready in time. 我將負(fù)責(zé)按時做好一切準(zhǔn)備。 You may depend on it that Tom will help you with your English.(你放心，湯姆會幫助你學(xué)英語的。) Im counting on it that you will come. 我指望著你會來。,It is amazing that at my age