Scientists who try to predict earthquakes have gotten some new helpers recently—animals.
　　That’s right, animals. Scientists have begun to understand what farmers have known for thousands of years. Animals often seem to know in advance that an earthquake is coming, and they show their fear by acting in strange ways. Before a Chinese quake in 1975, snakes awoke from their winter sleep early only to freeze to death in the cold air. Cows broke their halters (缰绳) and tried to escape. Chickens refused to enter their cage. All of this unusual behavior, as well as physical changes in the earth, warned Chinese scientists of the coming quake. They moved people away from the danger zone and saved thousands of lives.
　　One task for scientists today is to learn exactly which types of animal behavior predict quakes. It’s not an easy job. First of all not every animal reacts to the danger of an earthquake. Just before a California quake in 1977, for example, an Arabian horse became very nervous and tried to break out of his enclosure. The Australian horse next to him, however, remained perfectly calm. It’s also difficult at times to tell the difference between normal animal restlessness and “earthquake nerves”. A zoo keeper once called earthquake researchers to say that his cougar had been acting strangely. It turned out that the cat had an upset stomach.
　　A second task for scientists is to find out exactly what kind of warnings the animals receive. They know that animals sense far more of the world than humans do. Many animals can see, hear, and smell things that people do not even notice. Some can sense tiny changes in air pressure, gravity, or the magnetism of Earth. This extra sense probably helps animals predict quakes.
　　A good example of this occurred with a group of dogs. They were shut in an area that was being shaken by a series of tiny earthquakes. (Several small quakes often come before or after a large one.) Before each quake a low booming sound was heard. Each boom caused the dogs to bark wildly. Then the dogs began to bark during a silent period. A scientist who was recording quakes looked at his machine. It was acting as though there were a loud noise too. The scientist realized that the dogs had reacted to a booming noise. They also sensed the tiny quake that followed it. The machine recorded both, though humans felt and heard nothing.
In this case there was a machine to monitor what the dogs were sensing. Many times, however, our machines record nothing extraordinary, even though animals know a quake is coming. The animals might be sensing something we measure but do not recognize as a warning. Discovering what animals sense, and learning how they know it is a danger signal, is a job for future scientists.
【小题1】Through the passage the writer hopes to explore __________.

第二节 完型填空(共20小题；每小题2分，满分40分)　　
阅读下列短文，掌握其大意，然后从36～55各题的四个选项(A，B，C和D)中选出能填入相应空白处的最佳选项。并将答案写在答题卡上。
Shopping habits in the United States have changed greatly in the last quarter of the 20th century. 　36  in　 the 1900s most American towns and cities had a Main Street. Main Street was always in the heart of a town. This street was 37  on both sides with many 38  businesses. Here, shoppers walked into stores to look at all sorts of merchandise: clothing, furniture, hardware, groceries. 39  ,some shops offered 40  .These shops included drugstores, restaurants, shoe-repair stores, and barber or hairdressing shops. 　41  in　 the 1950s, a change began to 42  .Too many automobiles had crowded into Main Street 43  too few parking places were 44 shoppers. Because the streets were crowded, merchants began to look with interest at the open spaces 45  the city limits. Open space is what their car-driving customers needed. 　　
And open space is what they got 46  the first shopping centre was built. Shopping centres, or rather malls, 47  as a collection of small new stores 48  crowded city centres. 49 by hundreds of free parking space, customers were drawn away from 50  areas to outlying malls. And the growing 51  of shopping centres led 52   to the building of bigger and better?stocked stores. 53  the late 1970s,many shopping malls had almost developed into small cities themselves. In addition to providing the 54   of one stop shopping, malls were transformed into landscaped parks, 55   benches, fountains, and outdoor entertainment.　　
36.A.As early as     B. Early     C. Early as      D. Earlier　　
37.A.built          B.designed      C.intented        D.lined　　
38.A.varied       B.various       C.sorted  D.mixed up　　
39.A.Apart from    B.However     C.In addition   D.As well　　
40.A.medical care  B.food       C.cosmetics     D.services　　
41.A.suddenly     B.Abruptly     C.Contrarily    D.But　　
42.A.be taking place      B.take place   C.be taken place   D.have taken place　　
43.A.while        B.yet              C.though   D.and then　　
44.A.available for  B.available to  C.used by            D.ready for　　
45.A.over          B.from       C.out of       D.outside　　
46.A.when         B.while      C.since         D.then　　
47.A.started       B.founded         C.set up    D.organized　　
48.A.out of        B.away from   C.next to       D.near　　
49.A.Attracted          B.Surprised    C.Delighted     D.Enjoyed　　
50.A.inner         B.central     C.shopping      D.downtown　　
51.A.distinction     B.fame       C.popularity    D.liking　　
52.A.on          B.in turn     C.by turns       D.further　　
53.A.By         B.During     C.In           D.Towards　　
54.A.cheapness      B.readiness     C.convenience   D.handiness　　
55.A.because of     B.and         C.with          D.provided