完形填空II. 根据所学语段，用适当的词填空。请同学们务必看清题目要求，限做指定题目。(共8个小题；每小题1分，满分8分)

         Another drug that has helped increase the standard of people’s   41  is penicillin. This bacteria-killing medicine is considered by many to be one of the most   42   medicines in contemporary society. It was discovered by   43  Scottish scientist named Alexander Fleming in 1928. He noted that mould had grown on a special transparent jelly that had bacteria on it. Fleming tried this mould   44  on another bacterium and found that it killed the bacteriun   45  . He named the chemical found in the mould ‘penicillin’ and tried to make it pure to be a medicine.

  46    , it was not until World War Ⅱ   47   two other scientists managed to use new chemical techniques to purify it. They were able to produce it in large    48   .

 (湘郡生试题)   I was really surprised to find out that the first public showings of wireless TV transmissions took   41   way back in 1925. It took another three years before there was any regular public broadcasting.   42  , I think people must have found   43   quite a delight when color TV was first broadcast in 1929.   44   , within the next 65 years, people would be able to choose   45   to watch from a   46  of 200 different channels because   47  cable TV. It is reported   48  in 1998, 66 percent of households in the USA had cable TV.

第二部分 阅读理解（共25小题，第一节每小题2分，第二节每小题1分；满分45分）

第一节，阅读下面短文，从每题所给的四个选项（A、B、C和D）中，选出最佳选项，并在答题卡上将该项涂黑。

Bollworms are a traditional threat to cotton crops．Young ones feed on the boll，the part of the cotton plant that contains the seeds．

A bacterium known as Bt is able to kill bollworms and some other pests．Bt is the short form for Bacillus thuringiensis．It was discovered in the early twentieth century．Farmers began using Bt as a natural pesticide(杀虫剂)．

Then，in the 1990s，researchers found a way to grow cotton plants that contain a Bt gene．The genetically improved cotton plant produces liquid that kills bollworms．Farmers around the world are now growing an estimated fourteen million hectares of Bt cotton．

Cotton bollworms also attack other crops．But scientists in China recently reported that Bt cotton may help prevent bollworm in other crops growing nearby．

The study involved crops grown in six provinces of northern China between 1992 and 2008．The study area contained three million hectares of cotton and twenty-two million hectares of corn，peanuts，soybeans and vegetables．

The researchers say the study suggested that Bt cotton not only controls bollworm on the transgenic cotton，but also may reduce its existence on other crops．And that reduction，they say，may decrease the need for insecticide use in general．

But the researchers also pointed out concerns．They say bollworms could develop resistance to the cotton plants designed to resist them．And they noted that insects called mirids have become “key pests” of cotton in China．They said this is because of a decrease in pesticide use made possible by Bt cotton．

The researchers say they do not believe that Bt cotton alone can solve all insect problems．Instead，they say farmers in China should consider it just one part of pest management systems．

1．What is Bt in this passage?

A．It's a kind of hi-tech invention．                   B．It's a natural bacterium．

C．It's a kind of pest．                        D．It's a man-made pesticide．

2．Bt cotton has all the advantages EXCEPT that ________．

A．it resists bollworms

B．it does good to other crops growing around

C．it reduces the use of insecticide

D．it helps to develop new insects

3．The underlined word “ones” in the first paragraph refers to ________．

A．bollworms          B．cotton crops         C．cotton seeds        D．pests

4．From the passage，we can infer ________．

A．farmers around the world are now growing a large area of Bt cotton

B．researchers are probably now searching for new ways to solve other cotton problems C．bollworms could not exist in Bt cotton any longer

D．Chinese scientists found the way to grow Bt cotton

Bacteria(细菌) are extremely small living things. While we measure our own sizes in inches or centimeters, bacterial size is measured in micron. One micron is a thousandth of a millimeter; a pinhead is about a millimeter across, Rod-shaped bacteria are usually from two to four microns long, while rounded ones are generally one micron across. Thus, if you magnified a rounded bacterium a thousand times, it would be just the size of a pinhead, while a grown-up human enlarged by the same amount would be over a mile tall.
Even with an ordinary microscope(显微镜), you must look closely to see bacteria. Using a magnification of 100 times, one can hardly find bacteria. Nor can one make out anything of their structure(结构), of course. Only by using special colors, can one see that some bacteria have wavy-looking “hairs” called flagella. Others have only one flagellum. The flagella move round a central point, pushing the bacteria through the water. Many bacteria lack flagella and cannot move about by their own power, while others can move along over surface by some little-understood “machinery”.
From the bacterial point of view, the world is a very different place from what it is to humans. To a bacterium, water is as thick as molasses(糖浆) is to us. Bacteria are so small that they are affected by the movements of the chemical molecules(分子) around them. Bacteria under microscopes, even those with no flagella, often jump up and down in the water. This is because they knock with the water molecules and are pushed this way and that.
36. The underlined word magnified means _______________.
A. enlarged                                                      B. widened                  
C. killed                                                          D. caught
37. We know from the passage that _______________ is the smallest.
A. a pinhead                                            B. a rounded bacterium 
C. a microscope                                        D. a rod-shaped bacterium
38. The relationship between a bacterium and its flagella is most nearly like which of the following?
A. A rider jumping on a horse back 
B. A ball being hit by a bet
C. A boat powered by a motor    
D. A door closed by wind
39. Why does the writer compares water to molasses in the third paragraph?
A. To tell us how difficult it is for bacteria to move through water.
B. To suggest that bacteria are fond of different liquids.
C. To show different chemicals are of different structures.
D. To show that bacteria are the best swimmers.
40. Which of the following is the main topic of the passage?
A. The characteristic (特点) of bacteria.      
B. How bacteria reproduce.
C. The various parts of a bacterium’s body    
D. How bacteria cause diseases.            

第四部分：任务型阅读(共10小题；每小题1分，满分10分)

请认真阅读下列短文，并根据所读内容在文章后表格中的空格里填入一个最恰当的单词。

注意：请将答案写在答题卡上相应题号的横线上。每个空格只填1个单词。

For more than twenty years scientists have been seeking to understand the mystery of the‘‘sixth sense"of direction．By trying out ideas and solving problems one by one，they are now getting closer to one answer．

One funny idea is that animals might have a built-in compass(指南针)．

Our earth itself is a big magnet(磁体)．So a little magnetic needle that swings freely lines

itself with the big earth magnet to point north and south．When people discovered that idea about athousand years ago and invented the compass，it allowed sailors to navigate (航海)on oceanvoyages, even under

cloudy skies.

 Actuallly the idea of the living compass came just from observing animals in nature．

 Many birds migrate twice a year between their summer homes and winter homes．Some of them fly for thousands of kilometers and mostly at night．Experiments have shown that some birds can recognize star patterns．But they can keep on course even under cloudy skies．How can they do that?

A common bird that does not migrate but is great at finding its way home is the homing pigeon．Not all pigeons can find their way home．Those that can are very good at it，and they have been widely studied．

One interesting experiment was to attach little magnets to the birds’ heads to block their

magnetic sense—just as a loud radio can keep you from hearing a call to dinner．On sunny days, that did not fool the pigeons．Evidently they can use the sun to tell which way they are going．But on cloudy days，the pigeons with magnets could not find their way．It was as if the magnets had blocked their magnetic sense．

Similar experiments with the same kind of results were done with honeybees．These insects also seem to have a special sense ot direction．

In spite of the experiments，the idea of an animal compass seemed pretty extraordinary．How

would an animal get the magnetic stuff for a compass.

An answer came from an unexpected source．A scientist was studying bacteria that live in the

mud of ponds and marshes．He found accidentally little rod-like bacteria that all swam together in

one direction—north．

Further study showed that each little bacterium had a chain of dense particles inside，which

proved magnetic．The bacteria had made themselves into little magnets that could line up with the

earth’s magnet．

The big news was that a living thing，even a simple bacterium，can make magnetite．That led

to a search to see whether animals might have it.. By using a special instrument called magnetometer，scientists were able to find magnetite in bees and birds，and even in fish．In each

animal，except for the bee．the magnetic stuff was always in or closer to the brain．

Thus．the idea of a built—in animal compass began to seem reasonable．

Scientists believe that conditions on Mars around 3.8 billion years ago were very similar to those of the early earth, when primitive organisms were spreading through our oceans. At that time, Mars would have been much warmer and wetter than it is today, with an atmosphere composed mainly of carbon dioxide, just like that of the earth at the time. Under these conditions, it is highly probable that life may have arisen on Mars as well.

  But, even if life did not arise naturally on Mars, it does not mean that it could not have existed there. According to Professor Paul Davies of the University of Adelaide, Australia, life forms could have been transferred between the earth and Mars in wreckage (broke pieces) created by the impact of comet(彗星) and small planets on the surface of the two planets.

  Even today, about 500 tons of material from Mars lands on earth every year. It is mainly in the form of the dust but occasionally a larger chunk(厚片，大块) strikes the earth. In 1911, a piece of Martian rock crashed in Egypt, killing a dog. According to Professor Davies, it is in these chunks of rock, which were much larger and more frequent in the past that life forms could have been transported from planet to planet.

  “But how could these life forms have survived their journey through space?” says Paul Davies, “The difficulty in believing this theory is that a bacterium on its own in space has to struggle itself not only against cold but also against deadly cosmic (宇宙的) radiation. But wrapped in a rock the situation is different. A rock ten meters across would shield life inside it from a lot of radiation and the temperature might only be minus 10 or 20 degrees, the sort of thing we have on earth.”

Where do some scientists suppose life probably come from? (2’) (No more than 6 words)

What does Professor Paul Davies believe? (2’) (No more than 6 words)

Why could life survive when transferred from one planet to another? (3’) (No more than 12 words)

List at least two differences about Mars between the past and now. (3’) (No more than 16 words)