1. 名词作主语 直到河里的鱼死了，村民们才意识到污染的危害。The villagers didn't realize how serious the pollution was until the fish in the river died. S+V+O. 主系表结构 :S+V 倒装：Not until the fish in the river died did the villagers realize how serious the pollution was. 注意：倒装在主句，从句不倒装 did 和not 提前，只剩动词原形 强调：It was not until the fish died in the river that the villagers realized how serious the pollution was. 如果强调的是主语或宾语且指人用who，其他一律用that。是that，而非其他/主句的顺序（（倒装不强调，强调就不倒装）） 2.代词作主语 人称代词（主格），名词性代词，指示代词，不定代词，such（----样的人、物），it（时间，天气，距离等） at midnight /in the(泛指）middle of the night It is 9 o'clock when I went home. It was ten when I got home.一般句 It was at ten that I got home.强调句 I got home at ten.原形 3.数词作主语 Ten out of 100 Americans are over /above /more than 65. 4.动名词作主语 一般 / 完成时 v-ing: 主动/doing/having done not doing:被动/being done/having done 注意：doing 无时间限定/与谓语同时出现/在谓语动词后发生having done发生在谓语之前 He still remembers being prized. 当逻辑主语为无生命的东西时 a.作主语时，通常表示一般性的无时间性的东西。而不定式表示某一种具体的动作。 Smoking is hobbit difficult to break. b.主语和表语一致 Seeing is believing. c.逻辑主语必须是所有格形式 Smoking kills. d. it 作形式主语：It is no use/good… The old man's taking pity on the snake leads to his death.那个老头怜悯那条蛇，导致他的死亡。 5.不定式作主语 To + 动词原形 Not to do 解释：具有动词的性质，作宾语，状语/具有名词的性质，作主语/具有形容词性质，作定语/具有副词的性质，作状语。除谓语不可作之外，其他都可。 一般式：to do 进行时：to be doing 完成时：to have done 完成进行时：to have been doing to do:表示动作发生在谓语之后，I want to go home.与谓语动词几乎同时发生 to be doing :表示与谓语动词同时发生 to have done:发生在谓语动词之前 Someone was considered to have done something. to have been doing :动作从过去开始一直持续到谓语动词这个动作的发生 不定式表示一种确定的动作 To do morning exercises this morning is not good for your healthy. 注释：作主语在句首/it作主语构成（常用 v-ing，不常用只有 use，good） It is +adj. +of sb.(人的属性）/for sb.（物的属性）to do It is necessary to finish the design before National day. Tomorrow is National day. it is +n.+for/of sb. to do It is not good manners for Arabs to stand close talking to their friends. It is a great honor for us to be invited to the party. 在感叹句中必须用it作形式主语：What a joy/ pleasure (it is) to read the book. 在问句中必须用形式主语：Is it possible to go to the moon by spaceship? 6.名词化的形容词或过去分词 the poor / the disabled /the sick 7.名词化的介词短语 From my home to school is three kilometers. 副词----不定式或动名词 What an excitement to find a shark when you’re swimming in the sea. 8.句子作主语（从句一律为陈述句） 1)that引导的从句，无意义，不担当句子成分，不省略 A. It +v+ that从句 It +系动词+表语+that 从句 It is strange that he didn't come here yesterday. 当形容词为important necessary strange /that should +动词原形 It is strange that he should （表示吃惊）pass the exam. 2. It is +n +that 从句 What a pity it is that you didn't come to this party. 当名词为a pity/a shame /a surprise +should +v原形（表示竟然） What a pity that she should be fail in exam. 3. It is +过去分词+that 从句 It is report that a car accident happened there. 从句s +be v-ed + inf. He is said to be studying in the USA. 有人建议suggest/order/request + 从句 should +动词原形 4. It +动词原形seem/appear /turn out/+that It seems that it will rain. 5. It strikes sb. that 从句 ，某人突然想 It occurs to sb. that----- B.为强调从句意义，that从句常放在句首 That he will come here is of great help. That you failed the exam will --What made his father so angry? --That he failed the exam. 或He fails the exam. c.在问句中必须有形式主语 It is true that Bush will visit China again? 2) Whether /if是否不担当句子成分，也不省略 A.句首只用whether Whether he will come to the meeting is unknown yet. B.句末形式主语都可用 It ----whether/if It is of no/little important whether/if it will rain today. c.在有些句型中，从句不在前 It doesn't matter whether ---- It doesn't matter whether it is new/it will rain tomorrow. 3) 连接代词 who /whom/whose/what/which/担当从句成分，有意义，不省略 A. what +sb. + clause What we will do next is not decided. B. what+修饰词 意为什么样的…… What color you like is none of my business. C. what ……人，……事，……物 What he said at the meeting surprised everyone present. 注意：what前是否有先行词/与that 之间的区别 That he said it at the meeting surprised everyone present. What 与which 的区别 Which/what you want---若给定范围用which，没有用what。 What ---be that---强调句的一种（强调后者） What I need most is that someone helps me. There be +what clause There was we call People's Republic of China in Chinese history. What +比较级 what more /what worse what引导从句作状语修饰全句的内容。在句首或句中，很少在句尾 Which +n (single) Whose +n(只用此） Whose father is a doctor is no sense. It从句作形式主语（what……人或物时，不用it） 4）连接副词 when/whose/how/why 担当句子成分，有意义，不省略 How the accident happened puzzled everyone.句尾用形式主语it 5) 引导主语从句 whoever/whosever/whatever/whichever/Anywhere/anything that /everyone that/whoever=anyone whom/anything that (泛指)/anything what (特指) Whoever 指人从意义判断 Who 指事 Since the introduction of reform, China has made earth shaking changes.自从改革以来，中国发生了翻天覆地的变化。