Zebras have their own bug repellent(驱虫剂)?
Eww bugs! They are so annoying! We humans are lucky that we can apply repellents to avoid nasty bites. But what’s an animal to do? They have no choice but to spend their days shooing （赶走）them off with their tails, unless, of course, they are zebras, who apparently have their own automatic repellent--- their striped skin!
Scientists had originally thought that the reason why the animal had developed the black and white lines was to help protect itself from predators (食肉动物)in the African savannah(大草原), because the stripes make it difficult to single out one zebra that is traveling with a herd.While that may be true, the theory has never been tested or proven. Now the experts have another---that the stripes have evolved to repel the annoying horse flies that not only feed off their blood, but also, transmit dangerous germs into the bodies of these innocent animals.
The study was performed by a team of Swedish scientists. One of the clues that got them thinking along these lines was the fact that darker horses got bitten more often than light-colored or white ones.
The fact that zebras are born black and only develop stripes as they grow older made the scientists theorize that the stripes may be something the animals have developed to make themselves less attractive to flies.
To test if this may be the case, they painted some boards at a horse-infested(寄生的) horse farm in Budapest with patterns of black and white stripes of varying widths and applied a layer of glue on them. What they noticed was that the places where the black and white stripes were at their narrowest (similar to what zebras have) attracted the fewest flies. They achieved similar results when they painted horses with black and white zebra-like stripes.
While the research are not sure why this may be the case, they believe it may be something to do with the way insects operate---horseflies are attracted to horizontally polarized light(偏振光); since white does not reflect it, white horses are luckier than black ones. But zebras seem to be the luckiest of all. When the researchers measured the polarized light reflected from real zebra skins, they found that it matched light patterns that were the least attractive to horseflies.
While this theory does make logical sense, nobody is 100 percent sure that it is really true, given that it has never been tested on a real zebra. If it is true, it does raise the question of why a horse, a close relative of the zebra has failed to develop stripes. The researchers believe that this could be because there are more horseflies in Africa, where zebras reside（居住）, than anywhere else in the world.
| Title | Zebras have their own bug repellent? | |
| Reasons why zebras develop their strips | Original belief | With the black and white lines, one zebra is difficult to single out while traveling with a herd, thus ___71___ it from its enemies. |
| New theory | Zebras, residing in Africa where there are most horseflies in the world have developed strips to ___72____ being attacked. | |
| A study | Researchers | A team of scientists from __73___ |
| __74___ | To test if strips are developed to make zebras less attractive to flies. | |
| Clues | *White or light-colored horses are less __75___ to get bitten than dark ones. *Zebras develop strips as they grow older though born black. | |
| Method | *Some boards at a horse farm are painted with patterns of black and white stripes variously ___76___ , a layer of glue applied on them. *Measured the polarized light reflected from real zebra skins. | |
| ___77___ | *The places where the black and white stripes at the narrowest were similar to the ___78___zebras have attracted the fewest flies. *Strips of zebras matched light patterns that were the least attractive to horseflies. | |
| Principle of zebras’ black and white strips repelling the flies | Horizontally polarized light, which white does not reflect, ___79___ to horseflies. | |
| Conclusion | ___80___tested on real zebras, the theory isn’t definitely true. | |
71.protecting 72.avoid 73. Sweden 74. Purpose 75.likely
76.wide 77. Findings 78. ones 79. appeals 80. Unless
In a society, such as the United States or Canada, which has many national, religious and cultural differences, people highly value individualism--the difference among people. Teachers place a lot of importance on the qualities that make each student special. The educational systems in these countries show these values. Students don't memorize information. Instead, they work individually and find answers themselves. There is often discussion in the classroom. At an early age, students learn to form their own ideas and opinions.
In most Asian societies, by contrast, people have the same language, history, and culture. Perhaps for this reason, the educational system in much of Asia reflects society’s belief in group goals and purposes rather than individualism. Children in China, Japan, and Korea often work together and help one another in assignments. In the classroom, the teaching methods are often very formal. The teacher lectures, and the students listen. There is not much discussion. Instead, the students recite rules of information that they have memorized.
There are advantages and disadvantages to both of these systems of education. For example, one advantage to the system in Japan is that there much more math and science than American students learn by the end of high school. They also study more hours each day and more days each year than North Americans do. The system is difficult, but it prepares students for a society that values discipline and self-control. There is, however, a disadvantage. Memorization is an important learning method in Japanese schools, yet many students say that after an exam, they forget much of the information that they have memorized.
The advantage of the educational system in North American, on the other hand, is that students learn to think for themselves. The system prepares them for a society that values creative ideas. There is, however, a disadvantage. When students graduate from high school, they haven’t memorized as many basic rules and facts as students in other countries have.
Title： 76 of Educational System between North America and Asia
| Students in the US and 77 | Students in China, Japan and Korea | |
| What do they 78 | Individualism | 79 goals and purposes |
| Different 80 of study | Working individually | Listening to the teachers |
| Forming their own ideas and opinions | Reciting rules and memorizing information | |
| A lot of discussion in the classroom | Not much discussion | |
| 81 | Learning to think for themselves | Learning much more math and science |
| Studying more hours each day and more days each year | ||
| Good for a society that values 82 | Good for a society valuing 83 and self-control | |
| Disadvantages | Students haven’t memorized many basic rules and facts before 84___ | Information is 85 easily. |
Directions: Read the following passage. Complete the diagram by using the information from the passage. Write NO MORE THAN 3 WORDS for each answer.
American public education has changed in recent years. One change is that increasing numbers of American parents and teachers are starting independent public schools called charter schools.
In 1991, there were no charter schools in the Unite States. Today, more than 2300 charter schools operate in 34 states and the District of Columbia. 575. 000 students attend these schools. The students are from 5 years of age through 18 or older.
A charter school is created by groups of parents, teachers and community members. It is similar in some ways to a traditional public school. It receives tax money to operate a number of students. The charter school must prove to local or state governments that its students are learning. These governments provide the school with the agreement, or charter that permits it to operate.
Unlike a traditional public school, however, the charter school does not have to obey most laws governing public schools. Local, state or federal governments cannot tell it what to teach.
Each school can choose its own goals and decide the ways it wants to reach those goals. Class sizes are usually smaller than in many traditional public schools. Many students and parents say teachers in charter schools can be more creative.
However, state education agencies, local education-governing committees and unions often oppose charter schools. They say these schools may receive money badly needed by traditional public schools. Experts say some charter schools are doing well while others are struggling.
Congress provided 200 million dollars for establishing charter schools in the 2006 federal budget. But, often the schools say they lack enough money for programs. Many also lack needed space, District officials say they have provided 14 former school buildings for charter education. Yet charter school supporters say officials should try harder to find more space.
Title: 71.
| 72 ________ | Independent public school | ||
| Similarities between charter schools and traditional schools | ●73 ________ to operate U number of students ●Having to prove the students are learning ●Getting 74 ________ to operate from government | ||
| 75 __________ between charter schools and traditional schools | ●Not having to obey most laws for public schools ●Being free to decide the 76 ________ ●Being free to choose the goals and decide 77 ________ them ●There usually being 78 ________ students in charter schools’classes ●Having teachers who are more creative | ||
| Charter school's problems | Opinions from education departments | These schools receiving money badly needed by 79 ________ Not all doing well | |
| Opinions from charter schools | Lacking enough money Lacking 80．_________ | ||