Unit 4 Astronomy： the science of the stars

课件30张PPT。人教课标 高一 必修 3 Unit 4GrammarUnit 4 Astronomy the science of the stars主语从句及引导词主语从句在复合句中作句子的主语。引导主语从句的词有从属连词that, whether, if；连接代词who, whoever, whom, what, whatever, whose, which；连接副词when, where, how, why等。【例句呈现】 观察下列例句，指出其中所包含的主语 从句及引导词: 1. What is needed for a long trip is careful preparation. 该句中主语从句是 _____ _____，引导词为 _____。What is needed for a whatlong trip2. That Jay Zhou will come to my city excites everybody. 该句中主语从句是 _____ _____，引导词为 _____。 3. Whether we will travel abroad or not has not been decided. 该句中主语从句是 _____ _____，引导词为 _____。That Jay Zhou willWhether we willcome to my city thattravel abroad or notwhether4. Whoever knows the secret mustn’t tell others. 该句中主语从句是 _____ _____，引导词为 _____。 5. It remains a puzzle why dinosaurs died out suddenly long time ago. 该句中主语从句是 _____ _____，引导词为 _____。Whoever knows the whoeverwhy dinosaurs diedwhysecretout suddenly long long ago【观察总结】 通过分析上面例句，同学们可能会发现上面第5句中的主语从句似乎比较隐蔽。其实，这也是主语从句的一种呈现方式，即：当一个句子主语过长时，可以用it作形式主语，而把真正的主语或主语从句后移至句子末尾，以保持句子的平衡。注意观察下列例句中的划线部分：It is not clear how the accident happened. It is not hard to understand why he did so at that time. It is a pity that you should have made such a careless mistake. It is reported that more than thirty deaths were caused in the accident. 不难看出，虽然上面例句中都用it作 形式主语，但句子结构却不尽相同。 现将常见的由it作形式主语的句型总 结如下： 1. It is + n. + that 从句 2. It is + adj. + that 从句，常见此类形容 词有：important, necessary, clear, certain, natural, strange, obvious, likely, impossible, possible 等。3. It + 特殊动词 + that 从句 It seems / appears ... that ... 似乎…… It happened (to sb.) that ... （某人）碰巧…… 4. It + be + 过去分词 + 主语从句 It is said / reported / believed / suggested / known / proved that ...【要点精讲】 1. what 与 that 引导主语从句 观察下列例句，试着翻译例句并总结 其规律。 (1) What you lack is self-confidence. 译为：_____你所缺乏的是自信。(2) That more and more students are admitted into universities is true. 译为：_____ _____ (3) What is needed for the program is more wisdom. 译为：_____这个项目所需要的是更多的智慧。越来越多的学生将被大学录取的消息是真实的。从上面例句可以看出，that引导主语从句时，在句中具有“两不”原则： 一、不作句子成分； 二、没有实际意义。 当它引导的主语从句置于句首时，that不能省略；如果用it作形式主语，而把主语从句放在句末时， that可以省略。而what引导的从句则恰恰相反，what在从句中的作用为： 一、作句子成分； 二、除了起到引导从句的作用外还要承担具体的意义。【巩固练习】 用 what 或 that 填空。 (1) _____ he told us this morning was just a lie. (2) _____ is important to us is enough time. (3) It worries my mom _____ she is beginning to get a little fat. (4) _____ we can’t get seems better than _____ we have.WhatWh ... ...