【命題特點分析】

科普知識介紹文是中考英語閱讀理解選材的重要內(nèi)容，也是中考英語閱讀理解的考查難點。它著重向讀者介紹科學新發(fā)明、新發(fā)現(xiàn)、新創(chuàng)造，介紹生產(chǎn)新工藝、制造新方法，讓讀者了解科學知識，從而努力拼搏學好科學知識，并用所學科學知識為人民服務(wù)。因?qū)破罩R介紹文的內(nèi)容讀者缺乏相應了解，因此理解難度較大。同時科普知識介紹文中多會出現(xiàn)解釋性、定義 性、說明性長句，句子結(jié)構(gòu)較為復雜，因此閱讀時同學們一定要保持冷靜，切勿急躁，要始終保持平靜的心態(tài)。閱讀時應認真分析長句句子結(jié)構(gòu)和邏輯關(guān)系，這樣才能對其作出準確理解。相信只要投入地閱讀、審題、解題，是一定能讀懂科普知識介紹文并正確解答相關(guān)試題的。

科普知識介紹文常見題型如下：

1. 生詞詞義判斷題

不少科普知識介紹文介紹科學發(fā)明、科學發(fā)現(xiàn)和先進工藝流程，常出現(xiàn)一些反映現(xiàn)代科技的生詞，因此出現(xiàn)生詞詞義判斷題是理所當然的。這種試題常以科學新發(fā)現(xiàn)、新發(fā)明、新創(chuàng)造、工藝新流程為題點命制試題，常以What does the underlined word mean？或What is the meaning of the underlined word？或The underlined word means.為設(shè)問方式考查對生詞詞義的判斷和猜測。解題時一定要認真閱讀原文，分析原文對該科學新發(fā)現(xiàn)、新發(fā)明、新創(chuàng)造和工藝新流程是如何解釋、如何定義的，在此基礎(chǔ)上抽象概括出生詞詞義。

2. 代詞指代判斷題

科普知識介紹文在對科學新發(fā)現(xiàn)、新發(fā)明、新創(chuàng)造和工藝新流程進行解釋時，易出現(xiàn)動作變換多、人稱轉(zhuǎn)變頻的現(xiàn)象，因此常出現(xiàn)代詞指代判斷題。這些試題常以it， they， them等表示物的代詞為命題題點。解題時應認真分析動作轉(zhuǎn)換背景，區(qū)分動作的不同執(zhí)行者和承受者，從而準確判斷代詞的正確指代。

3. 科學方法圖示判斷題

科普知識介紹文常出現(xiàn)科學方法圖示判斷題，這種試題或以工藝流程為命題題點，要求考生判斷正確的流程順序，或以生產(chǎn)方法為命題題點，要求考生判斷正確的生產(chǎn)方法，或以機械配制為命題題點，要求考生判斷正確的機械配制。解題時一定要認真閱讀并分析原文對科學發(fā)明創(chuàng)造誕生過程的介紹和對工藝流程過程的介紹，并且邊讀邊畫簡易草圖幫助自己理解，思考備選項時應對照原文介紹情況，找出各圖不同之處，最終作出正確判斷。

4. 數(shù)字運算判斷題

這種試題常要求考生判斷某種發(fā)明創(chuàng)造使用時所能達到的高度、深度和寬度以及生產(chǎn)某種新產(chǎn)品的數(shù)量。解題時應認真閱讀并分析原文，尋找相應運算公式或運算規(guī)律。

5. 發(fā)明創(chuàng)造影響判斷題

這種試題常以What is the greatest influence of the new invention？或What is the be st effect of the new invention？或What is the most important result of the new in vention？為設(shè)問方式考查對發(fā)明創(chuàng)造影響的判斷。解題時應尋找原文介紹科學發(fā)明創(chuàng)造效果的內(nèi)容，從眾多效果中找出最佳效果。

6. 新產(chǎn)品使用方法判斷題

科學的發(fā)明創(chuàng)造都應推廣使用才能轉(zhuǎn)化為生產(chǎn)力，因此科普知識介紹文閱讀理解常出現(xiàn)產(chǎn)品使用方法判斷題，這種試題常以What is the correct way to use the new invention？或How can you use the new product？或What should we do to use the new product？為設(shè)問方式考查對新產(chǎn)品使用方法的判斷。解題時應認真閱讀原文介紹的新產(chǎn)品使用方法的注意點，從而得出新產(chǎn)品正確的使用方法。

7. 科普知識介紹內(nèi)容判斷題

一些科普知識介紹文介紹特定領(lǐng)域促進科技進步的不同方法，常出現(xiàn)科普知識介紹內(nèi)容判斷題。試題常以The passage tells us. 或The passage talks about.或The best title for the passage is.為設(shè)問方式，其答案常為differ ent ways to… 或how to use different ways to…。

【典型考題】

（一）

When you cut your skin， you bleed[流血]. If a person loses a lot of blood， he will become ill and may die. Blood is very important. People have always known that. At one time， some people even drank blood to make them strong！

When doctors understand how blood goes around inside the body， they try ways of giving blood to people who need it. They take blood from the healthy people and give it to people who need it. This is called “blood transfusion”. The blood goes from the arm of the healthy person into the arm of the sick person.

But there are two problems. First， it does not always work. Sometimes people die when they have blood transfusion. Later， doctors find that we do not all have the same kind of blood. There are four groups—O， A， B and AB. We all have blood of one of these groups. They also find that they can give any kind of blood to people of group AB. But they find that they must give A group blood to A group people and B group blood to B group people. I have O group blood and the doctor told me that I could give blood to anyone else safely.

There is another problem. To give blood of the right kind， doctors have to find a person of the right blood group. Often they can not find a person in time. If they have a way to keep the blood until someone needs it， they can always havet he right kind of blood. At first they find they can keep it in bottles for fifteen to twenty days. They do this by making it very cold. Then they find how to keep it longer. In the end they find a way of keeping blood for a very long time.

We call a place where we keep money a “bank”. We call a place where we keep blood a “blood bank”. One day， when you grow up， you may decide to give blood to a “blood bank”. In this way you may stop someone from dying. Or perhaps one day you may become ill. You may need blood. The “blood bank” will give it to you.

1. From the passage， we learn that sometimes people die when they have blood transfusions because they________________________.

A. are unhealthy people

B. have lost a lot of blood

C. are not given the right kind of blood

D. are AB group people

2. Which of the following is true？

A. Doctors can give any kind of blood to the writer.

B. The writer can give blood to B group people.

C. The writer has never had a blood transfusion.

D. The writer has the same kind of blood as his father_____________________.

3. People set up the “blood bank” so that they can.

A. give the right kind of blood to the people who need it in time

B. keep different groups of blood as much as possible

C. make it easier to sell or buy blood

D. keep blood for more than twenty hundred years

4. From the last paragraph[段落] of the passage， we learn that ________.

A. the writer thinks its good to give blood to a “blood bank”

B. we may become ill if we give blood to a “blood bank”

C. many people died because they lost a lot of blood

D. blood is more important than money

5. The writer doesnt talk aboutin the passage _________.

A. how important blood is to us

B. the four groups of blood

C. where the blood bank is

D. what “blood transfusion” is

（二）

How could we tell time if there were no watches or clocks anywhere in the world？

The sun was probably the worlds first “clock”， except in the far north， where the Eskimos[愛斯基摩人] live. There， its dark most of the winter， and light most of the summer. But in most of the world， people have used the sun for a clock. Even today， if you dont have a clock， you still know that when the sun shines， its day and when its dark， its night. The sun can also tell you if its morning， noon， or afternoon.

People who live near the sea can tell time from the tides. In the daytime， for about six hours， the water rises higher and higher on the beach. And then it goes down and down for about six hours. The same thing happens againat night. There are two high tides and two low tides every 24 hours.

Seamen on a ship learn how to tell time by looking at the moon and the stars. The whole sky is their clock.

In some places in the world the wind comes up at about the same time every day or changes direction or stops blowing. In these places the wind can be the clock.

A sand clock is an even better clock. If you had fine dry sand in a glass shaped like the one in the picture， you would have what is called an hourglass. The sand in the hourglass goes from the top part to the bottom part in exactly one hour. When the hourglass is turned over， the sand will take another hour to go back again.

1. According to the passage， there are____ways to tell time besides the clock and watch. A. 3 B. 4

C. 5 D. 7

2. The Eskimos in the far north cant use the sun for a clock because___________.

A. they know very little about the sun

B. the sun there never goes down in winter

C. its too cold for them to go out to watch the sun

D. it has long dark winters and long light summers

3. The underlined word “tides” in the passage means _________.

A. 洋流 B. 潮汐

C. 海嘯 D. 波浪

4. In which page of a newspaper can you most probably read this pas sage？

A. News

B. Science

C. Business

D. Advertisement

5. Whats the best title for the passage？

A. Different Ways to Tell Time

B. Useful Machines to Tell Time

C. The History of the Clock

D. The Development of the Clock

（三）

About ten men in every hundred suffer from colour blindness in some way. Women are luckier. Only about one in two hundred is affected in this matter. So some people say it is safer to be driven by women.

There are different forms of colour blindness. In some cases a man may not be able to see deepred. He may think that red， orange and yellow are all shades[色調(diào)] of green. Sometimes a person cannot tell the difference between blue and green. In rare cases an unlucky man may see everything in shades of green—a strange world indeed. Colour blindness in humans is a strange thing to explain. In our eyes there are millions of very small things called “cones”. These help us to see in bright light and to tell differences between colours. There are also millions of “rods”， but these are used for seeing when it is nearly dark. They show us shapes but no colour.

Some insects have favourite colours. Mosquitoes[蚊子] like blue but do not like yellow. A red light will not attract insects， but a blue lamp will. In a similar way humans also have favourite colours. Yet we are lucky. With the aid of the cones in our eyes we can see many beautiful colours by day， and with the aid of the rods we can see shapes at night. One day we may even learn more about the invisible[看不見的] colours around us.

1. With the help of the cones， we can ____________.

A. see in a weak light

B. tell different shapes

C. kill mosquitoes

D. tell orange from yellow

2. Why do some people say it is safer to be driven by women？

A. Women are more careful.

B. There are fewer colour blind women.

C. All of them see everything in shades of green.

D. None of them has trouble in recognizing[識別] colours.

3. This passage is mainly about ___________.

A. colour and its surprising effects

B. danger caused by colour blindness

C. colour blindness

D. the invisible colours around us