单选题The ______ is selling goods in the shop. [A] teacher [B] shop-assistant [C] worker

单选题______ is considered as America' s unique contribution to music. [A] Rock and Role [B] Jazz [C] Western and country music [D] Blues

单选题What inspired people's interest in Ovid once again?

单选题In paragraph 2, cities like London, Copenhagen, and Amsterdam are mentioned ______.

单选题 {{I}}Questions 14-16 are based on the following passage. You now have 15 seconds to read Questions 14-16.{{/I}}

单选题The author uses the example of cancer patients to show that______.

单选题______ that there is another good harvest this year. A. It is said B. It says C. He was said D. It was said

单选题Which of the following is NOT the feature of the ESS study program?

单选题Which of the following subjects was not included in those new courses of study?

单选题The fossil remains of the first flying vertebrates, the pterosaurs. have intrigued paleontologists for more than two centuries, How such large creatures, which weighed in some eases as much as a piloted hang-glider and had wingspans from 8 to 12 meters, solved the problems of powered flight, and exactly what these creatures were — reptiles or birds — are among the questions scientists have puzzled over. Perhaps the least controversial assertion about the pterosaurs is that they were reptiles. Their skulls, pelvises, and hind feet are reptilian. The anatomy of their wings suggests that they did not evolve into the class of birds. In pterosaurs a greatly elongated fourth finger of each forelimb supported a wing like membrane. The other fingers were short and reptilian, with sharp claws. In birds the second finger is the principal strut of the wing, which consists primarily of feathers. If the pterosaurs walked on ail fours, the three short fingers may have been employed for grasping. When a pterosaur walked or remained stationary, the fourth finger. and with it the wing, could only turn upward in an extended inverted V-shape along each side of the animal's body. The pterosaurs resembled both birds and hats in their overall structure and proportions. This is not surprising because the design of any flying vertebrate is subject to aerodynamic constraints. Both the pterosaurs and the birds have hollow bones, a feature that represents a savings in weight. In the birds, however, these bones are reinforced more massively by internal struts. Although scales typically cover reptiles, the pterosaurs probably had hairy coats. T.H. Huxley reasoned that flying vertebrates must have been warm-blooded because flying implies a high rate of metabolism, which in turn implies a high internal temperature. Huxley speculated that a coat of hair would insulate against loss of body heat and might streamline the body to reduce drag in flight. The recent discovery of a pterosaur specimen covered in long, dense, and relatively thick hair—like fossil material was the first clear evidence that his reasoning was correct. Efforts to explain how the pterosaurs became airborne have led to suggestions that they launched them- selves by jumping from cliffs, by dropping from trees or even by rising into light winds from the surfaces of waves Each hypothesis has its difficulties. The first wrongly assumes that the pterosaurs' hind feet resembled a hat's and could serve as hooks by which the animal could hang in preparation for flight. The second hypothesis seems unlikely because large pterosaurs could not have landed in trees without damaging their wings. The third calls for high waves to channel updrafts. The wind that made such waves however, might have been too strong for the pterosaurs to control their flight once airborne.

单选题 If adults liked to read books that were exceedingly difficult, they'd all be reading Proust. Most don't. So why, reading experts ask, do schools expect children to read—and love to read—when they are given material that is frequently too hard for them? Science and social studies textbooks are at least a grade above the reading levels of many students, experts say, and in some suburban and urban school systems, reading lists can include books hard for some adults to tackle. Toni Morrison's award-winning novel Beloved, about a former slave's decision to kill her child rather than see her enslaved, is on some middle schools' lists for kids to read unassisted. To be sure, pushing some students to challenge themselves is important, educators say. But there are points where kids read books before they can truly comprehend them and then lose the beauty of the work. "Teachers studied The Great Gatsby in college and then want to teach that book because they have smart things to say about it, and they teach it in high school, " Calkins said. "Then schools want to get their middle school kids ready for high school so they teach them The Catcher in the Rye. It's a whole cultural thing. " In large part, Dr. Richard Allington, a leading researcher on reading instruction and a professor of reading education at the University of Tennessee, blames inappropriately chosen books for students' reading woes, especially in school systems where large percentages of children read below grade level. The average fifth-grade student in Detroit and Baltimore, for example, reads at a third-grade level, he said, but schools still give them fifth-grade core reading and social studies texts. That, he said, crushes a child's motivation. "If you made me education magician and I had one thing that I could pull off, it would be that every kid in this country had a desk full of books that they could actually read accurately, fluently, with comprehension, " he said. Soft Sinozich, a seventh-grader in the Humanities and Communications Magnet Program at Eastern Middle School in Montgomery County, said she would like to be assigned books that speak to her. In sixth-grade English, "graphic novels were excluded, which annoyed many of us, " said Soft, who is partial to Japanese comics called manga because she finds the style beautiful and the stories well done. Many teachers exclude graphic novels and comics from reading lists, even though a graphic novel was nominated for the National Book Award this year. And Archbishop Desmond Tutu, a Nobel Peace Prize winner, has said he learned to read through comics after his schoolmaster father disregarded others who said they would lead to no good. So should kids read Shakespeare or the comics? Graphic novels or To Kill a Mockingbird? Reading experts say they should read everything—when they are ready to understand what they are reading.

单选题 In the 1950s, the pioneers of artificial intelligence (AI) predicted that, by the end of this century, computers would be conversing with us at work and robots would be performing our housework. But as useful as computers are, they're nowhere close to achieving anything remotely resembling these early aspirations for human like behavior. Never mind something as complex as conversation: the most powerful computers struggle to reliably recognize the shape of an object, the most elementary of tasks for a ten-month-old kid. A growing group of AI researchers think they know where the field went wrong. The problem, the scientists say, is that AI has been trying to separate the highest, most abstract levels of thought, like language and mathematics, and to duplicate them with logical, step-by-step programs. A new movement in AI, on the other hand, takes a closer look at the more roundabout way in which naturally came up with intelligence. Many of these researchers study evolution and natural adaptation instead of formal logic and conventional computer programs. Rather than digital computers and transistors, some want to work with brain cells and proteins. The results of these early efforts are as promising as they are peculiar, and the new nature-based AI movement is slowly but surely moving to the forefront of the field. Imitating the brain's neural (神经的) network is a huge step in the right direction, says computer scientist and biophysicist Michael Conrad, but it still misses an important aspect of natural intelligence. "People tend to treat the brain as if it were made up of color-coded transistors", he explains, "but it's not simply a clever network of switches. There are lots of important things going on inside the brain cells themselves." Specifically, Conrad believes that many of the brain's capabilities stem from the patternrecognition proficiency of the individual molecules that make up each brain cell. The best way to build and artificially intelligent device, he claims, would be to build it around the same sort of molecular skills. Right now, the option that conventional computers and software are fundamentally incapable of matching the processes that take place in the brain remains controversial. But if it proves true, then the efforts of Conrad and his fellow AI rebels could turn out to be the only game in town.

单选题 Unlike the private enterprise model，which is the foundation of the U．S．health care system，Canada has a health care system based on different principles：1) Universality：everyone is covered．2) Portability：people can move from province to province and from job to job，or be unemployed，and they will still be covered．3) Comprehensiveness：the plan covers all medically necessary treatment．4) Public administration：the system is pub-icly run and publicly accountable． Since 1947 Canada has had a tax-supported health care system in which every Canadian is covered for the costs of all medically necessary services．Under this plan，each citizen is issued a health card by the government，which is presented when health care is received．Using tax money，the government pays back physicians and hospitals，based on a fee schedule determined by the government，not the market．The keys are that the health services are paid for by the government and all Canadians have equal access to the care they need．Canadians can select any doctor they like．The plan is a“single payer” plan，with the doctors hilling the provincial insurance plans directly (the government of each Canadian province pays the medical bills of its citizens)．For patients，there are no bills，claim forms，fees，and long waits for compensations from insurance carriers． The key difference between the Canadian system and that in the United States is that“in Canada health care is considered a social right，while in the United States it is treated more like a commodity”． The usual arguments against such a plan are that it is inefficient and costly．In Canada’s case， health care is administered more efficiently，at less cost，and with better results，than the health care system in the United States．The results，as measured by infant mortality and life expectancy，show that Canada is ahead of the United States．Administrative costs are less in Canada (about one-fourth of U．S．administrative expenses for physicians，hospitals，and insurance companies)． The Canadian health care system is not perfect．Canadians have less access than Americans to the latest technological innovations．There may be waits for those not needing immediate surgeries．But despite some small problems，most Canadians like their health care system．A Gallup Poll in 1991 revealed，for example，that 91 percent of Canadians rated their health care system better than that in the United States，compared to only 26 percent of Americans who felt their system was superior to that in Canada．