摘要: 祈使句 + and + 陈述句结构 在这种句子结构中.祈使句表示条件.陈述句表示结 果.它相当于If you..., you will....另外.祈使句 + or + 陈述句结构表示:If (not)..., you will.有时候. 祈使句中的动词可省略. Work harder, and you'll find it not difficult to learn. 再用功一点.你就会发现它不难写. Hurry up, or you will be late. 快一点.否则你会迟到. More effort, and you can finish it in time. 再加把劲.你会按时完成它. [句型归纳] [考点1]Pierre and I did have a very good time at the ball. 皮埃尔与我确实在舞会上玩得很开心. 该句中的did为助动词.加强谓语动词have的语气. 在“助动词do / does / did + 动词原形 结构中.助动词 do / does / did意思是“确实.的确.一定 .常常用在 肯定句或祈使句中.起加强语气的作用.有人称和时 态的变化.例如: Do send me e-mail immediately you arrive at Beijing. 你 一到北京.一定要给我发电子邮件. He does smoke two packs of cigarettes every day. 他确 实每天抽两包烟. The company earned much more this month than it did last month. 公司本月赚的钱要比上个月多得多. [考例1] An awful accident , however, occur the other day. A. does B. did C. was to D. had to [考查目标] 对句子中谓语的强调. [答案与解析] B 助动词do 用于 对现在时态的强调,did用于对过去时态的强调.后面 均接动词原形. [考点2]In the eighteenth century, Benjamin Franklin conducted a number of experiments in which he showed what electricity is. 18世纪.本杰明·富兰克林做了一系 列的试验.以证明电是什么. 注意:该句子中的 a number of 作主语.谓语动词用复数 形式.例如: A number of children play video games online. 很多的 孩子在网上玩电子游戏. a number of意思是“许多.数目 .作主语时.谓语动词 用复数形式.the number of意思是“数量 .作主语时. 谓语动词用单数形式.例如: A number of people prefer to sending e-mail each other t0 writing letters. 许多人更愿意发电子邮件.而不愿意 写信. The number of milu deer is increasing year by year. 麋 鹿的数目在逐年增加. [考例2] The number of people invited fifty.but a number of them absent fnr different reasons. A. were; was B. was; was C. was; were D. were; were [考查目标] 主谓一致. [答案与解析] C 根据以上的解释.应该选was,were. [考点3]Having realized that I could use a kite to attract Iightning, I decided to do an experiment. 意识到可以用 风筝引来闪电之后.我便决定做个实验. 该句中的having realized是v-ing形式的完成式在句中 作状语. v-ing形式在句中的主要作用是作状语.having done表 示非谓语动词的动作先于渭语动词的动作.而且要注 意非谓语与句子主语之间存在着主动关系时.用hav- ing done,非谓语与句子主语之间存在着被动关系时. 用having been done,其否定形式是在v-ing前加not. 例如: Having finished his homework, the boy decided to play football for a while. 做完了作业.他决定去踢一会儿 球. Not having cleaned the classroom, they couldn't go home. 还没有打扫完教室.他们还不能回家. Having been praised in class, the girl felt very happy. 那个姑娘在班上得到表扬.感到很高兴. [考例3] from heart trouble for years, Professor White has to take some medicine with him wherever he goes. A. Suffered B. Suffering C. Having suffered D. Being suffered [考查目标]非谓语动词v-ing. [答案与解析]C v-ing形式的逻辑主语是Professor White.Professor White和suffer之间存在着主动关 系.而且根据.for years.表示 suffer 的动作持续换了 多少年.所以用v-ing完成式表示原因. [牛刀小试3]

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                            Preface

Science is a dominant(占优势的) theme in our culture. Since it touches almost every facet of our life, educated people need at least some acquaintance with its structure and operation. They should also have an understanding of the subculture in which scientists live and the kinds of people they are. An understanding of general characteristics of science as well as specific scientific concepts is easier to attain if one knows something about the things that excite and frustrate the scientist.

 This book is written for the intelligent student or lay person whose acquaintance with science is superficial; for the person who has been presented with science as a musty storehouse of dried facts; for the person who sees the chief objective of science as the production of gadgets; and for the person who views the scientists as some sort of magician. The book can be used to supplement a course in any science, to accompany any course that attempts to give an understanding of the modern world, or – independently of any course – simply to provide a better understanding of science. We hope this book will lead readers to a broader perspective on scientific attitudes and a more realistic view of what science is, who scientists are, and what they do. It will give them an awareness and understanding of the relationship between science and our culture and an appreciation of the roles science may play in our culture. In addition, readers may learn to appreciate the relationship between scientific views and some of the values and philosophies that are pervasive(普遍的;深入的)in our culture.

 We have tried to present in this book an accurate and up-to-date picture of the scientific community and the people who populate it. That population has in recent years come to comprise more and more women. This increasing role of women in the scientific subculture is not a unique incident but, rather, part of the trend evident in all segments of society as more women enter traditionally male-dominated fields and make significant contributions. In discussing these changes and contribution, however, we are faced with a language that is implicitly sexist, one that uses male nouns or pronouns in referring to unspecified individuals. To offset this built-in bias, we have adopted the policy of using plural nouns and pronouns whenever possible and, when absolutely necessary, alternating he and she. This policy is far form being ideal, but it is at least an acknowledgment of the inadequacy of our language in treating half of the human race equally.

 We have also tried to make the book entertaining as well as informative. Our approach is usually informal. We feel, as do many other scientists, that we shouldn’t take ourselves too seriously. As the reader may observe, we see science as a delightful pastime rather than as a grim and dreary way to earn a living.

According to the passage, ‘scientific subculture’ means

A  cultural groups that are formed by scientists. B  people whose knowledge of science is very limited.

C  the scientific community.    D  people who make good contribution to science.

We need to know something about the structure and operation of science because

A. it is not easy to understand the things that excite and frustrate scientists.

B Science affects almost every aspect of our life.

C Scientists live in a specific subculture.  D It is easier to understand general characteristics of science.

The book mentioned in this passage is written for readers who

A are intelligent college students and lay person who do not know much about science.

B are good at producing various gadgets.

C work in a storehouse of dried facts.    D want to have a superficial understanding of science.

According to this passage,

A English is a sexist language.  B only in the scientific world is the role of women increasing rapidly.

C women are making significant contributions to eliminating the inadequacy of our language.

D male nouns or pronouns should not be used to refer to scientists.

This passage most probably is

A. book review. B the preface of a book.  C the postscript of a book.  D the concluding part of a book.

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 "The world's oceans are slowly getting more acidic,”say scientists. The researchers from California report that the change is taking place in response to higher levels of carbon dioxide in the atmosphere.

    The lowering of the waters’pH value is not great at the moment but could cause a serious threat to current ocean life if it continues, they warn. Ken Caldeira and Michael Wickett, from the Lawrence Livermore National Laboratory, report their concerns in the journal Nature.

Increasing use of oil fuels means more carbon dioxide is going into the air, and most of it will eventually be absorbed by seawater. Once in the water, it reacts to form carbonic acid. Scientists believe that the oceans have already become slightly more acidic over the last century.

    These researchers have tried to predict what will happen in the future by combining what we know about the history of the oceans with computer models of climate change."This level of acidity will get much more extreme in the future if we continue releasing CO2 into the atmosphere," said Dr Caldeira. "And we predict the amount of future acidity will exceed(超过)anything we have seen over the last several hundred million years, let alone perhaps after rare disastrous events such as asteroid(小行星) impacts.”

    However, it is not absolutely clear what that means for ocean life.Most organisms live near the surface, where the greatest pH change would be expected to occur, but deep-ocean life forms may be more sensitive to pH changes.Coral reefs and other organisms whose shells contain calcium carbonate(小行星) may be particularly affected if the water's acidity levels keep going up, the team predict. They could find it much more difficult to build these structures in water with a lower pH.

    In recent years some people have suggested storing carbon dioxide from power stations in the deep ocean as a way of dealing with global warming.But Dr Caldeira said that such a strategy should now be re-considered. "Previously, most experts had looked at ocean absorption of carbon dioxide as a good thing-because in releasing CO2 into the atmosphere we warm the planet, and when CO2, is absorbed by the ocean, it reduces the amount of greenhouse warming.”

According to Dr Caldeira,__________ .

   A. ocean absorption of carbon dioxide is a good thing

   B. more oil fuels will be used in the near future

   C. scientists may predict climate changes with computer models

   D. the future situation of the amount of acidity is extremely serious

f the water's acidity level keeps rising,_________ .

   A. ocean life whose structures contain calcium carbonate may be affected

   B. the waters’pH value will become higher and higher

   C. organisms living near the surface are more sensitive to pH changes

   D. some disastrous events will occur more often than before

Most experts once believed storing carbon dioxide in the ocean would reduce________ .

   A. the CO2 absorbed by the ocean             B. the amount of greenhouse warming

   C. the acidity of the ocean                   D. the gradual release of CO2

The purpose of this passage is to_________ .

   A. show people the findings of a research team   B. inform people of how acid the ocean is now

   C. introduce Dr Caldeira and his team's research  D. warn people of the higher level of CO2

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