LECTURE 14 it专题本堂目标：熟悉指代性it及非指代性it的用法；重点掌握作先行词的it、引导强调句中it的用法。
基础预习一、指代性it指代性it指的是作人称代词的it。
it作人称代词时可指代事物、动物、婴儿、未知的人或一件事。
二、非指代性it非指代性it是相对于作人称代词的it而言的。
非指代性it没有具体意义上的主语，表示气候、天气、温度、时间、地点、距离等。
非指代性it常作seem，appear，look，happen，occur，follow等动词的主语，构成特定的句型。
重点讲解一、先行it1．it作形式主语it作形式主语，放在句首，将真正的主语（动词不定式、动名词、从句）放在后面，尤其当充当主语的动词不定式短语很长时，用it作形式主语，可以避免使整个句子头重脚轻，此时it不能用this或that 来代替。
1）it形式主语指代不定式it作形式主语指代不定式时，常见的谓语有：take, pay, make, cost, require, feel, annoy, need等，例如：It’s the hardest thing to take care of a teenager, have a job, pay the rent, pay the car payment, and pay the debt.2）it形式主语指代动名词【例】3）it形式主语指代从句2．it作形式宾语it作形式宾语放在谓语动词与宾语补足语之间，指代不定式、动名词、从句等。
后接it 作形式宾语的谓语动词有：feel, consider, find, believe, make, take, imagine, suppose, think, deem, regard, count等。
【例1】【例2】(02-Text 4)二、引导强调句的it当我们要强调句子的某一部分（通常是主语、宾语或状语）时，常用“it + be + 被强调部【例2】课堂练习难句分析1. However, whether such a sense of fairness evolved independently in capuchins and humans, or whether it stems from the common ancestor that the species had 35 million years ago, is, as yet, an unanswered question. (05-Text 1)2. It may be said that the measure of the worth of any social institution is its effect in enlarging and improving experience, but this effect is not a part of its original motive. (09-翻译)3. It’s not obvious how the capacity to visualize objects and to figure out numerical patterns suits one to answer questions that have eluded some of the best poets and philosophers. (07-Text 2)4. Furthermore, it is obvious that the strength of a country’s economy is directly bound up with the efficiencyof its agriculture and industry, and that this in turn rests upon the efforts of scientists and technologists of all kinds. (00-翻译)5. It is a rare and sophisticated patient who will challenge such professional decisions or raise in advance questions about price, especially when the disease is regarded as serious.6. There are slight regional variations among the French, German and Italian speaking areas, but it is generally safe to assume that any car bearing a CH sticker will be driven with a high degree of discipline.7. It has long been known that a taxi firm called AAAA cars has a big advantage over Zodiac cars when customers thumb through their phone directories. (04Text 2)8. It is said that in England death is pressing, in Canada inevitable and in California optional. (03Text 4)9. The best way to get a rapid and responsive answer is to ask it like a person with smarts, confidence, and clues who just happens to need help on one particular problem.10. And it is by the making of tools — physical tools as crude as a stone chopper, mental tools as subtle as a mathematical equation — that man characteristically prepares for future contingencies.11. It is this sudden confrontation with the depth and scope of ignorance that represents the most significant contribution of the 20th century science to the human intellect.12. It was not until the 13th and 14th centuries that surnames became fixed, although for many years after that, the degree of stability in family names varied considerably in different parts of the country.课堂讲评1. 【分析】整个句子是一个主系表结构，其中主语是由两个以whether引导的并列主语从句构成的，第二个从句的主语it指代前面的a sense of fairness，从句包含that引导的定语从句。
